Rod attaching/detaching device for a lifting jack and method of coupling suspending rods

ABSTRACT

A rod constituting a suspending rod is automatically connected or detached, and a rod is easily conveyed between a position where the rod is delivered to rod attaching/detaching means and a position where the rod is contained. A plurality of jacks are operated in synchronism. In the upper part of a boiler-side steel structure (58) is provided a boiler jack (60) for moving a boiler module (56) up and down via a suspending rod (52). Above the boiler jack is provided a device (68) for automatically attaching/detaching a rod. The device (68) is movable horizontally. The rod attaching/detaching device (68) grips a rod (52S) at the end of the suspending rod pushed up by the boiler jack, rotates it to remove, and transfer it to a rod conveyor device (70). Upon receiving the rod from the rod attaching/detaching device, the rod conveyor device conveys it ro a rod container (54) provided on a working floor (42). A plurality of jacks (60) are driven by synchronous output operation, the displacements of stroke of all the jacks are measured to find the differences between the minimum displacement and the other displacements, and the output of the jacks (60) of which the differences are larger than a set value are decreased so that the displacements are equalized to the minimum dieplacement.

TECHNICAL FIELD

This invention relates to a lifting jack, a method of couplingsuspending rods and a lift control method, more particularly, to: alifting jack having means for continuously attaching and detaching theend rod in order to adjust the length of the suspending rod which iselongated by the screwed coupling, and means for continuously removingand depositing the rod in accordance with attaching and detaching therod, when the suspending rod, which is used in a lifting operation for aboiler module of a large scale electric-power plant or the like, islifted up and down by the jack; a method of coupling suspending rods;and a lift control method for lifting up and down the boiler module orthe like while the lifting jacks are controlled in synchronism.

BACKGROUND ART

FIGS. 47 show a conventional suspending rod, used for lifting up amassive body, for example, when power-generation facilities are set up.A suspending rod 10, elongated by screwing plural rods 10S to each otherin the axis direction, is suspended from a beam portion, located at highelevations, of a steel structure to be used when a module of a boiler,associated with piping installation on the ground, is moved upward stepby step in response to the associating stages on the ground and moveddown as necessary. The rod 10S as a component of the suspending rod 10,which has a configuration continuously linked with plural top-shapedsupported portions 12 in the axis direction, has a male screw part 14 atthe end thereof and a female screw part 16 at the other end whichengages with the male screw portion of another rod. Each rod of thesuspending rod 10 is made to have the length of about 5 m inconsideration of a storage space of rods, convenience or handlingproperties for transferring them between workplaces, workability in thelifting operations for the massive body, and so on. In the use of thesuspending rod 10, the plural rods 10S are coupled by screwing eachother in the axis direction, and the massive body is lifted up by a jackwhile being suspended at the lower portion of the suspending rod 10.

More specifically, as shown in FIG. 48, steel columns 22 are stood uparound a heavy steel structure 20. A temporary beam 24 is horizontallymounted on the top of the steel column 22 to project from the top of thesteel column 22. A center hole type jack 26 is placed on the temporarybeam 24 and supports the suspending rod 10 attached with the heavy steelstructure 20, such as a module of a boiler, at the lower portionthereof. The suspending rod 10 is structured by coupling the rods 10Sshown in FIG. 47 so that the length of the suspending rod 10 correspondsto the height up to which the structure 20 is lifted. As shown in FIG.49, the center hole type jack 26 lifts up the structure 20 by pushing upthe suspending rod 10 with using the supporting part 12 formed in therod 10.

The lifting steps are as follows. As shown in FIG. 49(1), the suspendingrod 10, suspending the structure 20, is supported by an upper chuck 34,and the load of the structure 20 is received by the upper chuck 34, anda lower chuck 36 is released. In this state, a ram 32 is worked andpushes up the suspending rod 10 for a rod (one of the supported portions12) so as to lift up the structure 20 through the suspending rod 10. Thelower chuck 36 is closed when the suspending rod 10 is moved up for onerod, and the ram 32 is moved down so that the lower chuck 36 receivesthe lifting load (the suspending load) through the supporting part 12.When the lower chuck 36 supports the suspending rod 10, the upper chuck34 is opened to move further down the ram 32. When the upper chuck 34comes under the next supported portion, located beneath the supportedportion supported previously by the upper chuck 34, the upper chuck 34is closed again to support the suspending rod 10, and the lower chuck 36is opened, and the above steps are repeated. When the coupling point ofthe rod 10 reaches above the center hole type jack 26, the liftingoperations are intermitted in order to remove the top rod 10S.

Concerning the removing steps for the suspending rod 10, after the rod10S to be removed is held firm by equipment, such as a crane, not tofall or overturn, the top rod 10S, coupled and screwed, is rotated in adirection to release the coupling manually with the use of a tool, suchas a chain wrench, and then the top rod 10S is removed from itsconnecting rod 10S. The removed rod 10S is carried to a temporarystorage place on the temporary beam 24, on which the center hole typejack 26 is placed, by a device, such as a crane, or alternatively, it isbrought down on the ground for storing.

In the aforementioned method, the removed rod 10S should be moved downto the rod storage place positioned lower than the attaching/detachingposition of the rods, or conversely, the rod 10S which is placed in therod storage place should be moved up to the coupling position, thereforethe rod 10S is not effortlessly transferred. Moreover, conventionally,the rod is transferred by hand, so that a large amount of manual effortsis required in addition to the possible occurrence of a rod beingdropped.

The aforementioned lifting operations, using the hydraulic-actuatedcenter hole type jack 26 and the suspending rod 10, are applied in alifting operations for a large massive body, so that the coupling forcebetween the rods 10 should be large and a large force is needed torotate the suspending rod 10 in order to release the coupling.Additionally, the structure 20 must be lifted up while beinghorizontally balanced, so that plural center hole type jacks 26 are usedsimultaneously, and an operator takes charge of each center hole typejack 26, therefore workers are required in large numbers. Moreover, theoperations are carried out on the temporary beam 24 at high elevations,so that there is a disadvantage of the safety of workers.

When the heavy steel structure 20 is lifted up and down by using pluraljacks 26, the jacks 26 should be synchronously driven to lift up anddown and the stroke displacement of the ram 32 of each jack 26 should beequalised so that the heavy steel structure 20 is not inclined. Acontrolling method for equalising strokes of plural jacks is proposed,in which a pressure regulating valve is provided in the returning sideof a hydraulic jack and the stroke is equalised by adjusting the degreeof opening of the valve (Japanese Patent Laid-open No. Hei7-315774). Inthe adjustment of the degree of opening of the pressure regulatingvalve, when any one of the jacks produces stroke, the feed of oil isstopped and the pressure regulating valves of the other jacks areadjusted in order so that each jack produces stroke.

In the controlling method for equalising strokes of the jacks asdescribed in the above Patent Bulletin, the degrees of opening thepressure-adjusting valves of plural jacks are adjusted in order, so thatwhen a number of jacks are used, it takes time to adjust the degree ofopening of the valves, and additionally, a difference of the strokedisplacement between the jacks easily occurs for reasons of a change oftemperature in oil pressure during use, differences in time property ofeach device, and so on. Although the pressure regulating valves areadjusted in early stages, it is greatly difficult to equalise thestrokes of the jacks. Therefore, the massive body is laboriously liftedup and down in parallel, so that a bending force acts on the suspendingrod, and the valves must be adjusted again.

When the structure 20 is lifted, the plural center hole jacks 26 aresynchronized to be worked uniformly in order that the structure 20 islifted up not to incline, so that the removing operation for thesuspending rod 10 should be carried out invariably after the actions ofall center hole type jacks 26 are stopped. However, the number of cranesused for removing the rod 10S is limited, so that the plural rods 10Sare sequentially removed in order by plural cranes, therefore the entireoperating time period, including a time for lifting up the structure 20and a time for removing the rods 10S, is longer and the workingefficiencies are decreased. In addition, the safety of workers should befurther considered for reasons of a drawn-out operation. In order to setthe removed rod 10S on the temporary beam 24 or the ground, equipment,such as a crane, is required. The number of cranes or the like should becorresponded to the number of center hole type jacks 26. Therefore, asthe number of equipment used is increased, the number of operators forthe equipment is increased, resulting in expanding work schedules andcomplications for management.

DISCLOSURE OF THE INVENTION

In order to resolve the aforementioned disadvantages of the conventionalart, it is the first object of the present invention to provide alifting jack and a method of coupling suspending rods, which has asuspending rod attaching/detaching means capable of automaticallyseparating or coupling rods constituting the suspending rod.

It is the second object to improve the efficiency of work byautomatically separating and coupling the rod, constituting thesuspending rod, with the suspending rod attaching/detaching means, andby carrying out the smooth convey of the rods between a rod deliveryposition to the rod attaching/detaching means and a rod storingposition. At this time, the convey of the rods between the rod deliveryposition and the rod storing position can be properly carried out byreducing the efforts required in the conveying process for the rods, andadditionally, a means for easily changing a distance of a convey routeof the rod convey means is provided.

It is the third object of the present invention to provide a liftingjack and a lift control method, which has a means for carrying out asynchronizing control for a group of lifting jacks which is capable ofsimply controlling in synchronism the group of jacks suspending thesuspending rod not to produce the tilt of a module lifted, andhorizontally lifting up and down the lifted body.

In order to achieve the aforementioned objects, the lifting jackaccording to the present invention has a means for automaticallyattaching/detaching the suspending rod. The suspending rodattaching/detaching means, which is a device for attaching and detachinga rod to and from an end of a suspending rod when the suspending rod forlifting is formed by screwing and coupling the rods in the axisdirection and the top end portion of the suspending rod is lifted up anddown by the jack, has a chucking means for chucking a head part of therod; a rotation unit having a shaft driven to be rotated by a rotatingmotor and connected with the chucking means, and having a displacementabsorbing means on a path of linking an output shaft of the rotatingmotor to the chucking means; an elevating means for vertically movingthe rotation unit in response to screw pitch of the rods; a rotationsensor detecting the rotation of the chuck means; and a controllingmeans for finding the amount of the vertical movement of the chuck meansfrom an output signal of the rotation sensor, and for vertically movingthe rotation unit through the elevating means in response to the amountof the vertical movement. It is advisable that the displacementabsorbing means, placed on the path of linking the output shaft of therotating motor to the chuck means, has a shaft direction displacementabsorbing means and a rotation shaft run-out displacement absorbingmeans.

The operation of the attaching/detaching means as described above hasthe steps of: opposing a screw part of the rod to a screw part of thetop rod of the suspending rod while gripping the rod with the rotationchuck means; detecting a predetermined shaft direction displacement ofthe chuck means, caused by rotating the chuck means at a low speed atthe opposing position; and rotating the chuck means at a high speedwhile moving down a rotation unit, driving to rotate the chuck means, inresponse to screw pitch of the rod to couple the rods by screwing. Thepredetermined amount of the shaft direction displacement of the chuckmeans can be defined to be a value corresponding to a pitch of a rodcoupling screw. When the rod is coupled to an end of a suspending rodfor lifting which is formed by screwing and coupling the rods in theaxis direction, it is carried out by the steps of: gripping the rod in asuspending state with the rotation chuck means; rotating the rotationchuck means at a low speed while the rod is being centered on a screwpart of the top rod of the suspending rod; inserting a screw portion ofthe gripped rod by moving down a rotation chuck; detecting apredetermined shaft direction displacement of the chuck means with theengagement in the rotation at a low speed by using back-lash of a screwface; and rotating the rotation chuck means at a high speed while movingdown a rotation unit, driving to rotate the chuck means, in response toscrew pitch of the rod to couple the rods by screwing.

In consequence, when the rod is separated and removed, a differencebetween an ascending speed of the chuck means and an ascending speed ofthe rotation unit is absorbed by the displacement absorbing means, sothat the rod is automatically removed smoothly and swiftly to avoidincrease of torque, caused by the difference of speed. When the rods arecoupled, a difference of a descending speed of the chuck means and adescending speed of the rotation unit is also absorbed by thedisplacement absorbing means. The rotation shaft run-out, caused by thedeviated axes in screwing the rods or the like, is absorbed by the shaftrun-out displacement absorbing means, so that the rods are smoothly andeffortlessly screwed to each other.

The lifting jack according to the present invention has a means fordepositing and removing the rod onto and from the aforementioned rodattaching/detaching means. The means has a rod attaching/detachingmeans, which is positioned above the jack placed on a supporting frame,and provided to move from the attaching/detaching position; and a rodconvey means for continuously conveying the rods while circulatingbetween a position to deliver the rod through a gripping position, whichis provided on a moving route of the rod attaching/detaching means, anda rod storing position. The rod convey means has a frame assembled withmodules and having a direction changing portion of a sprocket or thelike to change directions of a conveyed body, and is changed in acirculating distances thereof according to changing of working positionsof the deliver position for delivering the rod to theattaching/detaching means and the rod storing position, thereby thedistance of the convey route of the rod convey means is easily changedand the rod deliver position and the rod storing position can beselectively set up.

In consequence, when the operations for separating and coupling the rodsconstituting the suspending rod is carried out automatically, the conveyof the rod between the rod deliver position for delivering the rod tothe rod attaching/detaching means and the rod storing position can beeasily carried out. The convey of the rod between the rod deliveryposition and the rod storing position is carried out by the rod conveymeans, not by hand, so that the efforts required for conveying the rodis reduced and the convey of the rod is dependably performed.

The lifting jack supports the boiler module as a lifted body, and pluraljacks are used for supporting it. The module as the lifted body shouldbe lifted up and down not to tilt, so that the synchronizing control fora group of the lifting jacks is carried out. A lift control method,according to the present invention, of a synchronizing control for agroup of lifting jacks, in which a massive body is lifted up and down byplural lifting jacks, has the steps: driving the lifting jacks to liftin an operation with equal output, and finding a deviation with respectto the minimum displacement by detecting stroke displacement of eachjack; and decreasing the output of the jack, having the deviationexceeding a predetermined value, to equate to the stroke displacement ofthe jack having the minimum displacement. When the output of the jackhaving the deviation exceeding the predetermined value is decreased, theoutput can be decreased at a predetermined rate with respect to theinitial output. When the deviation does not result in zero within apredetermined time although the output has decreased, the output can bedecreased at a predetermined rate at several times. The jack, decreasedwith the output thereof, retrieves the original output when the strokedisplacement equates to the stroke displacement of the jack having theminimum displacement.

The method of the synchronizing control can be achieved by the lift jackhaving the following synchronizing control unit for the group of thelifting jacks. It has a sensor to detect each stroke displacement of thelifting jacks; a flow regulating valve provided at each hydrauliccircuit of the jacks; and a controlling means for reading each detectingsignal from sensors, and for selecting the jack, having the minimumstroke displacement, as a reference jack when each jack is operated withan equal output, and for equating the stroke displacement of the jack,having the deviation to stroke displacement of the reference jackexceeding a predetermined value, to the stroke displacement of thereference jack by decreasing the output of the jack through the flowregulating valve.

According to the above structure, a jack having the minimum displacementof stroke is found, and each output of the other jacks may be decreasedto be coordinated to the reference jack, so that the synchronizingcontrol can be relatively easily carried out and the lifted body can belifted in approximately horizontal. Especially, when the output of thejack is decreased, the output may be decreased to be an output definedat a predetermined rate with respect to the initial output, therebysimply carrying out the synchronizing control. When the deviation doesnot result in zero within the predetermined time after the output hasbeen decreased, the output of the above jack can be decreased step bystep at a predetermined rate, thereby the overshooting, in which thestroke displacement of the jack, being controlled, is decreased underthe stroke displacement of the reference jack by reason of theover-decreased output, can be avoided. When the deviation is zero, bycontrolling to recover the output of the jack which has been decreased,the complicated and accurate output control is not needed and thecontrol without complication and the simplification of apparatus can beachieved.

In the above description, the lifted body is the boiler module, but thelifted body is not limited to the boiler module, so that the presentinvention can be applied when the lifted body is supported with thesuspending rod and lifted up and down by the jack.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic view of an entire lifting jack apparatusaccording to the preferred embodiment of the present invention;

FIG. 2 is a fragmentary sectional side view of a jack device for aboiler, according to the preferred embodiment;

FIG. 3 is a sectional view indicated by arrow A in FIG. 2, and also aplane view of an upper chuck unit according to the preferred embodiment;

FIG. 4 is a sectional view taken along the C--C line in FIG. 3;

FIG. 5 is a side elevational view of the upper chuck unit of whichsensor bracket is removed, according to the preferred embodiment;

FIG. 6 is a sectional view indicated by arrow B in FIG. 2, and also aplane view of a detent mechanism;

FIG. 7 is an exploded block components view of the jack device for aboiler and a rod attaching/detaching device of the embodiment;

FIG. 8 is a sectional view of a rotation unit of the rodattaching/detaching device according to the preferred embodiment of thepresent invention;

FIG. 9 is a front view of the rotation unit of the rodattaching/detaching device of the preferred embodiment;

FIG. 10 is a sectional view taken along the H--H line in FIG. 9;

FIG. 11 is a sectional view taken along the I--I line in FIG. 9;

FIG. 12 is a sectional view taken along the J--J line in FIG. 9;

FIG. 13 is a vertically sectional view of the rod attaching/detachingdevice of the preferred embodiment;

FIG. 14 is a front view of the rod attaching/detaching device of whenthe rotation unit is removed, according to the preferred embodiment;

FIG. 15 is a sectional view taken along the K--K line in FIG. 14;

FIG. 16 are a plane view showing an attaching state of a sensor fordetecting the vertical position of the rotation unit of the rodattaching/detaching device of the preferred embodiment, and a sectionalview (the L--L line);

FIG. 17 is a sectional view taken along the M--M line in FIG. 16;

FIG. 18 a side elevational view of a rod conveyor device according tothe preferred embodiment;

FIG. 19 is a back elevational view of the rod conveyor device accordingt o the preferred embodiment;

FIG. 20 is a plane view of the rod conveyor device according to thepreferred embodiment;

FIG. 21 is an enlarged plane view showing a delivering portion of therod conveyor device in detail, according to the preferred embodiment;

FIG. 22 are fragmentary sectional views (taken along the N--N line andthe O--O line) of the rod conveyor device;

FIG. 23 are a plane view and a front view showing an attaching state ofa rod detecting sensor located at a rod removing port in the rodconveyor device of the preferred embodiment;

FIG. 24 is a side elevational view of a balance device supporting alifted structure, according to the preferred embodiment of the presentinvention;

FIG. 25 is a front view of the balance device supporting the liftedstructure, according to the preferred embodiment;

FIG. 26 is a diagram showing an arranging state of the jack for theboiler when the lifting jack apparatus is seen from the front, accordingto the preferred embodiment;

FIG. 27 is an explanatory view of a synchronism controller for thelifting jack according to the preferred embodiment;

FIG. 28 is a block diagram of a jack controller of the preferredembodiment;

FIG. 29 is a fragmentary block diagram of the synchronism controller forthe lifting jack of the preferred embodiment;

FIG. 30 is a flow chart for explaining the flow of signals of thesynchronism controller for the lifting jack according to the preferredembodiment;

FIG. 31 are schematic views for explaining a part of processes fordetaching a rod according to the preferred embodiment;

FIG. 32 are schematic views for explaining a part of the processes fordetaching the rod in succession to the processes in FIG. 31;

FIG. 33 are schematic views for explaining a part of theprocesses fordetaching the rod in succession to the processes in FIG. 32;

FIG. 34 is a flow chart for explaining the detaching operation of therod by the rod attaching/detaching device according to the preferredembodiment;

FIG. 35 is a flow chart for explaining an ascending speed control for arotation unit by the rod attaching/detaching device according to thepreferred embodiment;

FIG. 36 are schematic views for explaining a part of processes forattaching the rods by the rod attaching/detaching device according tothe preferred embodiment;

FIG. 37 are schematic views for explaining a part of the processes forattaching the rods in succession to the processes in FIG. 36;

FIG. 38 are schematic views for explaining a part of the processes forattaching the rods in succession to the processes in FIG. 37;

FIG. 39 is a flow chart for explaining the attaching operation of therod by the rod attaching/detaching device according to the preferredembodiment;

FIG. 40 is a flow chart for explaining a descending speed control of therotation unit by the rod attaching/detaching device according to thepreferred embodiment;

FIG. 41 is a flow chart for explaining an upper-limit position controlof a chuck in the attaching state of the rods by the rodattaching/detaching device according to the preferred embodiment;

FIG. 42 is a flow chart for explaining a lower-limit position control ofa chuck in the attaching state of the rods by the rodattaching/detaching device according to the preferred embodiment;

FIG. 43 are explanatory views of a method for detecting irregularitiesin the rotation of a attaching/detaching chuck of the rodattaching/detaching device according to the preferred embodiment;

FIG. 44 is a program analysis diagram for explaining a synchronismcontrolling method of the lifting jack according to the preferredembodiment of the present invention;

FIG. 45 is a program analysis diagram showing the case in which theoperating state of the jack is changed in the synchronism control of thejack, according to the preferred embodiment;

FIG. 46 is a graph for explaining an example of changing stroke of thejack which is controlled by the synchronism controlling method of thelifting jack, according to the preferred embodiment;

FIG. 47 are a plane view and a front view of a conventional suspendingrod;

FIG. 48 is an explanatory view of the condition in which the suspendingrod is lifting a boiler module; and

FIG. 49 are explanatory views of a lifting method with the conventionalsuspending rod.

BEST MODE FOR CARRYING OUT THE INVENTION

Specific embodiments of a lifting jack, a method of coupling suspendingrods and a lift control method according to the present invention willbe described below in detail with reference to the accompanyingdrawings.

FIG. 1 is a diagrammatic view showing an entire jack system for a boileras lifting jack apparatus of the present invention. In FIG. 1, a workingfloor 42 is constructed on a boiler steel frame 40 composing a boilerchamber. On the working floor 42, a control panel 44; a hydraulic unit46 for driving a boiler jack or the like, which will be described later;and an operation panel 50 operated by an operator 48 are provided. Inaddition, a rod container 54 for storing rods 52S used for composing asuspending rod 52 is provided on the working floor 42. Contiguous to theboiler steel frame 40, a boiler-side steel frame 58 for lifting up anddown a boiler module 56, as a lifted body, is constructed.

The boiler module 56 is supported and suspended by a boiler jack 60 as acenter hole type hydraulic jack, which will be described later, throughthe suspending rod 52 of which the plural rods 52S are coupled by beingscrewed in the axis direction. More specifically, an upper frame 64 isconstructed in the upper portion of a column 62 of the boiler-side steelframe 58. The boiler jack 60 is placed on the upper frame 64. The boilermodule 56 is supported through the suspending rod 52 and lifted up anddown by alternately working chucks, each located in the upper portionand the lower portion of the boiler jack 60.

Above the boiler jack 60, a rod attaching/detaching device 68 as a rodattaching/detaching means which will be described later is placed on aframe 66, in which the top (end) rod 52S1 located above the boiler jack60 is uncoupled from and coupled to a rod 52S2, located directly beneaththe rod 52S1. Under the rod attaching/detaching device 68 and adjacentto the boiler jack 60, a rod conveyor device 70 as a rod convey means isprovided in order to convey and store the rod 52S, removed by theattaching/detaching device 68, into the rod container 54 provided on theworking floor 42, in likewise to deliver the rod 52S, stored in the rodcontainer 54, to the rod attaching/detaching device 68.

As shown in FIG. 2, the boiler jack 60 is composed of a cylinder 74 as afixed outer cylinder member, standing up on the upper face of abox-shaped ram chair 72 placed on a temporary beam, and a ram 76inserted in the cylinder 74. The cylinder 74 has a double-wall structureand accommodates the ram 76 in the wall thereof to allow the ram 76 tomove up and down. An oil pressure chamber has a feed oil chamber 78,placed on the inserting end portion under the bottom face of the ram 76,and a return oil chamber 80 which is placed on a side wall portion ofthe ram 76, partitioned by the lower end portion of the ram, above thefeed oil chamber 78. The ram 76 is moved up by feeding working oil intothe feed oil chamber 78 and moved down by opening the feed oil chamber78 to feed the working oil into the return oil chamber 80.

The boiler jack 60 is provided with a center hole 82 at the centralportion thereof to pass the suspending rod 52. The boiler jack 60 keepshold of a neck portion -formed in the suspending rod 52 to support theboiler module 56 connected to the suspending rod 52, while allowing theboiler module 56 to lift up with the driving of the ram 76. In order tosupport the neck portion of the rod, an upper chuck unit 84 is providedon the top end of the ram of the jack 60, and a lower chuck unit 86 isprovided in the ram chair 72 placed in the lower portion of the cylinder74. FIGS. 3 to 5 show the above structure in detail with the upper chuckunit 84.

FIG. 3 is a sectional view indicated by arrow A in FIG. 2. FIG. 4 is asectional view taken along the C--C line in FIG. 3. FIG. 5 is a sideelevational view when a sensor bracket 100 (see FIG. 3) is removed. Asshown in the drawings, the upper chuck unit 84 is provided with anopening at the central portion thereof and a rectangular-shaped chuckbase 88 which is secured on the top face of the ram 76. On the upperface of the chuck base 88, a pair of chucks 90, divided into halves, aremounted to slide horizontally. The chucks 90 are opened and closed atthe divided portion. In order to control the opening and closingdirection of the chucks 90, inverted L-shaped slide guides 92 arearranged along a pair of opposed edges of the chuck base 88, and engagedwith both of the side edge portions of each chuck 90. On the rear edgeportion of each chuck 90, a bracket 94 is secured. Both of the endportions of the bracket 94 are connected to a hydraulic cylinder 96 fordriving the pair of right and left chucks 90 to open and close. Thehydraulic cylinder 96 is positioned above the upper face portion of theslide guide 92, and is expanded and contracted along the guidingdirection to open and close the chucks 90 with the action of expandingand contracting.

The upper chuck unit 84 has two semi-circular top plates 98 which engagewith the neck portion in the suspending rod 52 when the chucks 90 areclosed. More specifically, the chuck 90 is formed to have a half-roundrecess, having a larger diameter than that of the neck in the suspendingrod 52, on the half-divided portion. The chuck 90 is firmly providedwith the top plate 98 having the half-round recess so that a circularopening approximately corresponding to the diameter of the neck isformed on the top face portion when the chucks are closed.

On each outer side face of the slide guides 92, an inverted L-shapedsensor bracket 100 is secured. The end of the sensor bracket 100 is bentdownward in L-shape to form a lower step portion than the upper face ofthe top plate 98. On the lower step portion, an open sensor 102detecting that the chucks 90 are opened and a close sensor 104 detectingthat the chucks 90 are closed are arranged. Note that the lower chuckunit 86 has a similar structure to that of the aforementioned upperchuck unit 84, but the lower chuck unit 86 is provided in the ram chair72 to chuck the suspending rod 52 under the cylinder 74.

The boiler jack 60 according to the embodiment is adjusted to allow thelength of the rod 52S, composing the suspending rod 52, to equal a unitof an up-down stroke, therefore, the boiler jack 60 is structured tohave the up-down stroke longer than the length of the rod 52S. As shownin FIG. 2 and FIG. 5, the suspending rod 52 is elongated by coupling theplural rods 52S in the axis direction. In each rod 52S, a rod head 52Bof a larger diameter is formed on an upper portion of a rod part 52A. Amale screw part 52C is formed on a lower portion of the rod part 52A. Afemale screw part 52D is formed on the side face formed in the centralportion of the rod head 52B. The plural rods 52S are screwed and coupledin the axis direction by screwing the female screw part 52D with themale screw part 52C of another rod 52S. The rod 52S has a groove 52E forpreventing itself from falling, which engages with a projection placedan engaging claw of the rod attaching/detaching device 68, on theperiphery of the top of the rod head 52B.

The suspending rod 52 as described above is enabled to support a load bybeing chucked by the chuck unit. In the boiler jack 60, the upper chuckunit 84 and the lower chuck unit 86 simultaneously chuck the rod 52S andthe rod 52S positioning under the previous rod 52S, and additionally,the state that the upper chuck unit 84 supports a load can be shifted tothe state that the lower chuck unit 86 supports a load. When the ram 76is changed from the descending position to the ascending position, thestate that the lower chuck unit 86 supports a load can be moved to thestate that the upper chuck unit 84 supports a load. This is madepossible by defining the up-down stroke of the ram 76 to be slightlylonger than the length of the rod 52S.

When the lower chuck unit 86 is assigned to support the load of thesuspending rod 52, the ram 76 can be moved up by opening the upper chuckunit 84, and the rod 52S can be coupled or uncoupled at the top end ofthe suspending rod 52. The plural rods 52S are coupled between thesupported position by the lower chuck unit 86 and the top end of thesuspending rod 52, so that, especially when the screwing of the top rod52S is released and the top rod 52S is separated, unscrewing of thescrewing portions positioned under the top rod 52 in the center hole 82might occur. For this reason, a detent mechanism is provided forstopping the rotation caused between the rod 52S2, lifted up by movingup the ram 76, and the rod 52S3, projected from the upper portion of thecylinder 74 and is to be lifted up after the rod 52S2 (see FIG. 2), inan ascending mode for lifting up the boiler module 56 and detaching therod 52S.

The frame 66 as a rigid-frame construction, constructed for stablysupporting the upright standing jack 60, is provided on the periphery ofthe boiler jack 60 (see FIG. 2), so that the strategic points of thejack 60 are supported by the frame 66. In the frame 66, defining the rod52S2 as an object that is stopped rotating, which is directly coupled tothe top of the rod 52S3 which is to be chucked by the upper chuck unit84 at the upper portion of the ram 76 moved down, the detent mechanism110 is provided in a transverse beam portion 106 placed at a position ofthe height of the larger-diametrical rod head 52B of the rod 52S2 (seeFIG. 6).

As shown in FIG. 6 of the sectional view indicated with arrow B in FIG.2, the detent mechanism 110 has a pair of turnable arms 112. The endportions of the arms 112 are opened and closed by a hydraulic cylinder114 linking the arms, and pressuring blocks 116, provided at the endportions opening or closing, clamp the larger-diametrical rod head 52Bof the rod 52S2 with pressure. For the purpose of opening and closingthe pressuring blocks 116 at the center line on the axis of the boilerjack 60, the turnable arm 112 is attached onto a mounting beam 118,arranged parallel to the transverse beam portion 106, with a turningshaft 120 at some midpoint thereof, and the end portion of the arm 112,which is in the vicinity of the hydraulic cylinder 114, is slidablyturned in the horizontal in the transverse beam portion 106. Thereby, apair of turnable arms 112 clamp the larger-diametrical rod head 52B withthe driving force caused by the hydraulic cylinder 114 while beingguided to turn horizontally by the mounting beam 118 and the transversebeam portion 106, and then stops the whirl.

The top rod 52S1 can be automatically coupled and uncoupled by providingthe aforementioned detent mechanism 110. The structural example is shownin FIG. 7. As shown in the drawing, a transverse drive shaft 134constituted of a screw shaft is placed above the boiler jack devicesarranged in two rows. The rod attaching/detaching device 68 is providedto move to a position above any one of the adjacent boiler jack deviceswith the guide of the transverse drive shaft 134. In the rodattaching/detaching device 68, an attaching/detaching chuck (chuckingmeans) 140 located under a rotation unit 138 which will be described indetail later is rotated by a rotating motor 142 provided with aservo-motor. Additionally, the rotation unit 138 is moved up and down byan elevating motor 144 provided with a servo-motor as an elevatingmeans. After the attaching/detaching device 68 is moved to and stoppedat a position directly above one of the boiler jack devices, theattaching/detaching device 68 is moved downward to grip the rod head 52Bof the top rod 52S1 which is located directly on the rod 52S2 stoppedwhirling, and rotationally driven to release the screwing of the rods,whereby the top rod 52S1 is detached. On the other hand, in a descendingmode in which the rod 52S is coupled to the suspending rod 52, the rodattaching/detaching device 68 delivers the rod 52S1 being to be coupled,and is rotationally driven to screw the rod 52S1 to the rod 52S2 stoppedwhirling, whereby the rods are coupled.

As shown in FIG. 8, in the rotation unit 138, a guide shaft 150 issecured onto an output shaft 146 of the rotating motor 142 via acoupling 148. Under the rotating motor 142, a casing 152 covering thesurrounding of the coupling 148 is fixed and rotatably supports theguide shaft 150 via a bearing 154. To the lower portion of the guideshaft 150, a cylindrical slide shaft 156, having the bottom face andconstituting a shaft direction displacement absorbing means, is movablyconnected in the axis direction, so that the displacement of the shaftdirection of the attaching/detaching chuck 140 to the guide shaft 150 isabsorbed. A sliding key 158 is provided to the guide shaft 150 to avoidthe rotation of the slide shaft 156 about the guide shaft 150. On theupper circumferential portion of the slide shaft 156, a compressionsprings 160 is arranged to forcibly push up the slide shaft 156 to carryout a floating support.

More specifically, on the periphery of the compression spring 160, aspring holder 162 secured on the bottom of the casing 152 is placed. Inthe lower portion of the spring holder 162, a spring seat 164 passedthrough the slide shaft 156 is placed. The compression spring 160 islocated between the spring seat 164 and a flange-shaped spring shoe 166formed on the upper portion of the slide shaft 156. In the lower portionof the spring holder 162, a bearing 168 is placed on the periphery ofthe spring seat 164 to rotatably support the slide shaft 156 via thespring seat 164.

On the bottom end of the slide shaft 156, the attaching/detaching chuck140 is attached via a spring coupling 170 as a rotation shaft run-outdisplacement absorbing means. The attaching/detaching chuck 140 is anair chuck, and has three grip claws 172 in the lower portion thereof forgrasping the head 52B of the rod 52S, and a pneumatic driven part 174driving the opening and closing of the grip claws 172. On each innerface of the grip claws 172, a projection 176 is formed to engage thegroove 52E, formed on the rod head 52B of the rod 52S and prevent thegrasped rod 52S from falling. On the top face of the pneumatic drivenpart 174, a rotation detecting plate 178 for a rotation sensor detectingthe rotation of the attaching/detaching chuck 140, which will bedescribed in detail later, is placed in order to lift up and down therotation unit 138 in synchronization with the rotation of theattaching/detaching chuck 140.

Above the spring coupling 170, a distance detecting plate 180 fordetecting the amount of deflection of the compression spring 160 issecured to the slide shaft 156. On the lower outer circumferential faceof the spring holder 162, a ring support 182 is fixed (see FIG. 9), onwhich four spring expansion sensors 184, 186, 188 and 190 are attachedto be opposite the distance detecting plate 180. The spring expansionsensors 184, 186, 188 and 190 consist of a limit switch, a workingtransformer, a linear encoder, a photosensor or the like, and arepositioned at a distance from one another in a diagonal arrangement inthe axis direction of the slide shaft 156. Each of the spring expansionsensors detects the distance to the distance detecting plate 180therefrom and inputs the detection signal into a control system forcontrolling the attaching/detaching device (not shown). Each of thespring expansion sensors 184 to 190 change to ON when the distance tothe distance detecting plate 180 becomes less than a predeterminedvalue, and OFF when the distance exceeds the determined value.

The spring expansion sensor 184 is for detecting the contracting limitof the compression spring 160, and is activated and turns ON when thedistance between the distance detecting plate 180 and the sensor 184 isless than a predetermined value d_(MIN), whereupon the control systemstops the rotation of the attaching/detaching chuck 140 and raises analarm. When the attaching/detaching chuck 140 does not suspend the rod52S, the distance between the spring expansion sensor 186 and thedistance detecting plate 180 is defined to be less than a value d₀. Thespring expansion sensor 186 changes into the ON position when thedistance between the distance detecting plate 180 and the sensor 186 isless than a value d₀. The spring expansion sensor 188 changes into theOFF position when the distance between the distance detecting plate 180and the sensor 188 further drops less than a predetermined value d₁, forexample more than d₁ +5 mm, in consequence whereof the compressionspring 160 is stretched out by the weight produced when theattaching/detaching chuck 140 grasps and suspends the rod 52S. As willbe described later, the control system decreases the ascending speed ofthe rotation unit 138 when the spring expansion sensor 188 is in the OFFposition in the uncoupling step of the rod 52S, whereas the controlsystem increases the descending speed of the rotation unit 138 in thecoupling step of the rod 52S. And, the spring expansion sensor 190 isfor detecting the expanding limit of the compression spring 160, andchanges into the OFF position when the distance between the distancedetecting plate 180 and the sensor 190 exceeds a predetermined valued_(MAX), whereupon the control system stops the rotation of theattaching/detaching chuck 140 and raises an alarm.

The rotation detecting plate 178 is structured as shown in FIG. 10, inwhich plural (six in the embodiment) rotation detecting slots 192 areopened to be spaced 60 degrees from each other about the center of theplate 178 on the margin of the plate 178. The rotation detecting plate178 is shaped in an arc-shaped oval along the circumferential edge ofthe rotation detecting plate 178. In addition, plural (three in theembodiment) basic point holes 194 are formed on the rotation detectingplate 178. The basic point holes 194 are arranged to be spaced 120degrees from each other about the center of the rotation detecting plate178, each of the holes 194 being formed at a position closer to thecenter of the rotation detecting plate 178 than the rotation detectingslots 192 and at a position corresponding to the middle point of therotation detecting slot 192 in the longitudinal direction. Under therotation detecting plate 178, a rotation detecting sensor 196 and a homeposition detecting sensor 198, consisting of a photosensor, forrespectively detecting the rotation detecting slot 192 and the referencehole for home position 194, are placed (see FIG. 9). The length of therotation detecting slot 192 along the circumference of the rotationdetecting plate 178 corresponds to the length of the space between therotation detecting plates 178 along the circumference of the rotationdetecting plate 178. A duty rate of an ON ("H") signal and an OFF ("L")signal, outputted from the rotation detecting sensor 196 when therotation detecting plate 178 rotates a turn at a fixed speed, is definedas 50%.

As shown in FIG. 11, the rotation detecting sensor 196 and the basicpoint sensor 198 are attached on an mounting bracket 200 secured on theupper face of a steady plate 199. The steady plate 199 has an arc shapeshorter than a semicircle and is secured on the upper face of a flangeportion 202 of the pneumatic driven part 174 to avoid the vibration,caused by the rotation of the attaching/detaching chuck 140, incooperation with a steady plate 204 secured on the flange portion 202opposite the steady plate 199.

On the outer edge portions of the steady plates 199 and 204, mountingplates 206 stand at both sides of the attaching/detaching chuck 140 inthe diameter direction. Steady guides 208 are respectively attached tothe mounting plates 206 to orient toward the outside, and engaged withguiding grooves formed on rectangular cylinder-shaped guide supports 210located at the both sides of the attaching/detaching chuck 140 to avoidthe vibration of the attaching/detaching chuck 140 and guide thevertical movement of the attaching/detaching chuck 140 along the guidesupport 210. As shown in FIG. 9, a pair of the guide supports 210 aresecured to the side portion of the casing 152 via a fixing bracket 212at the upper end portion thereof.

On the lower end portion of a pair of the steady guide 208, a sensormounting ring 214 shown in detail in FIG. 12 is secured. On the upperend of the sensor mounting ring 214, two pairs of support plates 216 and218 are secured to overhang into the sensor mounting ring 214 (see FIG.12). In a pair of the support plate 216, a grip sensor 220, consistingof a light emitting portion and a light receiving portion for detectingthat the grip claws 172 of the attaching/detaching chuck 140 close togrip the rod 52S, is attached to confront each other to detect thegripping by means of changing into the ON position when the grip claws172 grip the rod 52S. In the other pair of the support plate 218, a griprelease sensor 222 consisting or a light emitting portion and a lightreceiving portion is attached to confront each other to detect therelease of the gripping of the rod 52S by the attaching/detaching chuck140 by means of changing into the OFF position when the grip claws 172move backward between the light emitting portion and the light receivingportion.

In the lower end portion of the sensor mounting ring 214, a pair ofnotches 224 are formed. A bracket 226 secured to the steady guide 208via the notch 224 is projected inside the sensor mounting ring 214. Atthe ends of the brackets 226, a head detecting sensor 227 for detectingthe movement of the head 52B of the rod 52S into the grip claws 172 ofthe attaching/detaching chuck 140 is attached to confront each other.The head detecting sensor 227, consisting of a light emitting portionand a light receiving portion, is placed away from the center to eitherside of the attaching/detaching chuck 140 as seen from the top. Abovethe sensor mounting ring 214, a tight sensor 230 is secured to each ofthe steady guides 208 via a bracket 228 to confront each other (see FIG.9). The tight sensor 230 consists of a light emitting portion and alight receiving portion, and is placed parallel to the head detectingsensor 227 along a linearly symmetrical position to the head detectingsensor 227 with respect to the center of the attaching/detaching chuck140 as seen from the top. And additionally, the tight sensor 230 detectsthat the upper end of the grip claw 172 of the attaching/detaching chuck140, namely, the slide face of the grip claw 172 gets in contact withthe top face of the rod heat 52B of the rod 52S. The contact between theslide face of the grip claw 172 and the rod head 152B is detected,whereby the down-movement of the attaching/detaching chuck 140 isfinished and the closing operation of the grip claws 172 is permitted.

As shown in FIG. 13, the rotation unit 138 is attached to a nut 234screwed with a screw shaft 232 rotated by the elevating motor 144. Morespecifically, as shown in FIG. 14 and FIG. 15, a cross-sectionalC-shaped elevating frame 240 composed of a pair of side plates 236 and aback plate 238 is attached to the nut 234. The back side of the casing152 of the rotation unit 138 is secured to the elevating frame 240. Theelevating frame 240 is vertically movable with respect to across-sectional C-shaped guide frame 242.

The guide frame 242 has a pair of side plates 244 and a connection plate246 joining the side plates 244. Guide rails 248 are oriented in thevertical direction of the opposed inner faces of the side faces 244.Each guide rail 248 engages guide bearings 250, attached on the upperand lower portions of the outer face of each side plate 236 of theelevating frame 240. The guide bearing 250 is guided by the guide rail248, whereby the rotation unit 138 is vertically movable along the guideframe 242 through the elevating frame 240.

The guide frame 242 has a motor mounting plate 252 at the upper endthereof, the elevating motor 144 being secured on the motor mountingplate 252 (see FIG. 14). Under the motor mounting plate 252, asupporting plate 254 is placed. A support unit 256 passed with a screwshaft 132 therethrough is attached on the supporting plate 254 torotatably support the upper portion of the screw shaft 232. The lowerportion of the screw shaft 232 is rotatably supported in a bearing unit260, consisting of a thrust bearing and a radial bearing, attached in abearing bracket 258 provided on the connection plate 246 of the guideframe 242. The lower portion of the screw shaft 232 is passed throughthe bearing bracket 258 and attached thereto with a rotary encoder 262for detecting the rotational speed of the screw shaft 232. An outputsignal of the rotary encoder 262 is sent to the control system forfeedback.

As shown in FIG. 13, the guide frame 242 is supported to move on across-sectional C-shaped transverse frame 264 in the horizontaldirection. The transverse frame 264 is secured to a main frame 266 asshown in FIG. 7. The transverse frame 264 rotatably supports thetransverse drive shaft 134, consisting of a screw shaft, through abracket. A transverse drive motor 268 is connected to the end of thetransverse drive shaft 134. The transverse drive shaft 134 is rotated byrotationally driving the motor 268, so that the rod attaching/detachingdevice 68 is moved in the horizontal direction. More specifically, atransverse nut 270, secured on the back face of the guide frame 242 ofthe rod attaching/detaching device 68, is screwed to the transversedrive shaft 134 (see FIG. 13), and moves in the axis direction with therotation of the transverse drive shaft 134, so that the rodattaching/detaching device 68 is lateraled in the horizontal direction.In the upper portion and the lower portion of the front face of thetransverse frame 264, guide rails 272 and 274 parallel to the transversedrive shaft 134 are provided respectively. Guide bearings 280 and 282,placed on the back face of the guide frame 242 with a upper bracket 276and a lower bracket 278, are respectively engaged with the guide rails272 and 274. The load of the attaching/detaching device 68 is supportedby the guide bearings 280 and 282. In addition, the lateral movement ofthe attaching/detaching device 68 can be smoothly carried out.

As shown in FIG. 16(1), an elevating position sensor 284 for detectingthe elevating position of the rotation unit 138 is placed on the sideportion of the guide frame 242. As shown in FIG. 16(2), the elevatingposition sensor 284 is composed of a pair of photo-couplers 286 and 288which are arranged in the vertical direction. The photo-couplers 286 and288 are respectively secured on the outer face of the side plate 244 ofthe guide frame 242 with sensor brackets 290. The photo-couplers 286 and288 are activated by a striker 294 which is secured on the outer sideface of the side plate 236 of the elevating frame 240 with mountingbrackets 292. Each mounting bracket 292 of depressed cross-section isattached to the striker 294 on the inner face of a side wall part 296thereof which is located toward the outside. As shown in FIG. 17, theend of the inverted L-shaped striker 294 is inserted between a lightemitting portion and a light receiving portion of the photo-couplers 286and 288. The width of the end of the striker 294 is similar to the widthbetween a pair of the photo-couplers 286 and 288 which are arranged inthe vertically direction. When the striker 294 moves to above thephoto-coupler 286 or when the striker 294 moves to under thephoto-coupler 288, the control system stops the lifting movement of therotation unit 138 and raises an alarm.

The rod conveyor device 70, as shown in FIG. 18 and FIG. 19, consists ofa conveying frame 730 which is assembled with modules of an upper frame732, an intermediate frame 734 and a lower frame 736. In addition, aninverted L-shaped transverse frame 738 is placed in the middle portionof the upper frame 732 in the vertical direction to extend toward therod attaching/detaching device 68 (not shown) so that the end portion ofthe transverse frame 738 is located under the rod attaching/detachingdevice 68. In the conveying frame 730, the upper frame 732, theintermediate frame 734 and the lower frame 736 are screwed to oneanother vertically, in order from top, so that the assembly anddisassembly are smoothly carried out. In addition, the length of thetransferring route in the vertical direction can be easily changed byplacing the intermediate frame 734, having an any given length, betweenthe upper frame 732 and the lower frame 736 or by changing the number ofintermediate frames 734. The length of transferring route in thetransverse direction (the horizontal direction) can be easily changedalso by adding frame members to the end of the transverse frame 738.

In the conveying frame 730, the lower frame 736 is located on theworking floor 42 as the storage place of the suspending rods as shown inFIG. 1. The transverse frame 738 is placed under the main frame 266 ofthe rod attaching/detaching device 68, in which the upper end potion ofthe transverse frame 738 (the right side of FIG. 18) is a deliveryposition for the rod. A manual jack 739 is placed at the bottom of eachvertical member 737 of the lower frame 736 to adjust the height of theconveying frame 730.

In the lower portion of the lower frame 736, a transfer drive motor 740capable of rotating in both directions is provided. A drive pulley 742is secured to a drive shaft of the motor 740 which is extended towardthe conveying frame 730. A drive belt 746 is wound on the pulley 742 anda pulley 744 which is rotatably provided to the side portion of thevertical member 737 of the lower frame 736. Under the pulley 744, a belttension 749 for adjusting the tension of the drive belt 746 is placed tothe vertical member 737 which supports to rotate the pulley 744 with arotating shaft 748. As shown in FIG. 19, the rotating shaft 748 attachedwith the pulley 744 spans across a pair of the vertical members 737 andis thereto secured with a pair of drive sprockets 750 as a changingdirection portion, the sprockets 750 combinedly rotating with the pulley744. As will be described in detail later, a conveying chain 752 fortransferring the rod 52S as a transferred object is wound on each drivesprocket 750. On the other side portion of the lower frame 736 which isopposite the side portion provided with the pulley 744, a control panel754 having a controller for controlling the conveyor device 70.

A pair of driven sprockets 756 as a changing direction portions arerotatably attached to the upper end of the transverse frame 738 of theupper frame 732. A pair of idle sprockets 758 are rotatably attached tothe upper base end supported portion of the transverse frame 738. Andalso, a pair of tension sprockets 760 are rotatably attached on theperiphery of the base end supported portion of a lower transverse frame759 of the transverse frame 738. The conveying chain 752 wound on thedrive sprocket 750 circulates between the working floor 42 as the rodstorage place and the delivery position placed in the end portion of thetransverse frame 738 through the sprockets 758, 756, and 760.Incidentally, the idle sprockets 758 are located in the loop formed bythe conveying chain 752 and the tension sprockets 760 are out of theloop.

As shown in FIG. 20, rod carrying members 790 for transferring the rods52S are slidably bridged across a pair of the transferring chains 752with appropriate spaces from each other along the chain 752.

As shown in FIG. 18, a point vertical member 780 composing thetransverse frame 738 is detachably attached with a post 782 and isprovided with a manual jack 784 on the top thereof, so that the endportion of the transverse frame 738 is extendedly fixed between asupporting floor (not shown) and the main frame 266 of the rodattaching/detaching device 68. The drive sprocket 750 and the idlesprocket 758 are located on an approximately diagonal line of thevertical direction of the conveying frame 730. Under the conveying chain752 running between the sprockets 750 and 758, a guide rail 786 isoriented along the chain 752. The guide rail 786 prevents the conveyingchain 752 from sagging when the rod 52S as a transferred object is heldin the rod holding member 790 attached on the transferring chains 752.The rod holding member 790 holding the rod 52S is driven to betransferred at any time by the transferring chains 752 positioning inthe upper side of FIG. 18. In other words, when the rod 52S removed fromthe suspending rod 52 is transferred to the working floor 42 where therod container 54 is placed, the conveying chain 752 is driven tocirculate in a counterclockwise direction of FIG. 18. On the other hand,when the rod 52S is transferred to the rod attaching/detaching device68, the conveying chain 752 is driven to circulate in a clockwisedirection of FIG. 18.

As shown in FIG. 21, the rod holding member 790 has a rod hanger 792supported by a pair of the transferring chains 752 and a rod retainingseat 794 secured on the central upper face of the hanger 792. A bearing796 is secured on each upper face of the ends of the rod hanger 792 topivotally support an end of a pin 798. The other end of the pin 798 issupported in a hanger bracket 802 attached to the conveying chain 752with a hook 800 as shown in FIG. 22(1) as a sectional view taken alongthe N--N line of FIG. 21. In consequence, the rod hanger 792 is slidablysupported by the pin 798 via the bearing 796, so that the rod retainingseat 794 is positioned in the upper portion of the rod hanger 792 atevery position on the convey route.

As shown in FIG. 22(2), both end potions of the rod hanger 792 areformed to have a vertically-flat quadrate cylinder shape, in which theside bottom portion of each end portion is a higher step than thecentral bottom face of each end portion. Each step bottom face 803 is incontact with an upper face of a guide plate 810 shown in FIG. 21 andFIG. 22, and is guided in the direction, in which the conveying chain752 circulates, by the guide plate 810. Each guide plate 810 is securedon the top face of an end of a supporting member 808 horizontallyprovided on each opposed face of an upper transverse member 804 of thetransverse frame 738 with a bracket 806. An opening 812 is formed toreceive the rod 52S at the central portion of the side face of the rodhanger 792. In each side of the opening 812, a screw bolt 814 is passedand screwed in the horizontal direction. A weight 816 is screwed to thescrew bolt 814 in order to adjust the balance when the rod 52S is heldin the rod holding member 790. The rod retaining seat 794 has an opening818 to receive the rod part 52A of the rod 52S at a positioncorresponding to the opening 812 of the rod hanger 792, and a seat 820to place the rod head 52B of the rod 52S on the periphery of the centralportion of the vertical direction of the opening 818.

On one of the hanger brackets 802 (in the left side of FIG. 22), aninverted L-shaped striker 822 is secured toward the outside. A pair ofholding member sensors 824 and 826 for detecting the approach of thestriker 822 moved by the conveying chain 752 are provided (see FIG. 21).The sensors 824 and 826, each having a light emitting portion and alight receiving portion, are structured with a reflection typephotosensor which detects light reflected from the striker 822, andsecured on a sensor bracket 828 standing up on the bracket 806. Theholding member sensor 826 is positioned on the side of the sensorbracket 828 which is located nearer to the transverse frame 738 than theother side of the sensor bracket 828 on which the holding member sensor824 is positioned, and detects that the rod 52S delivered from the rodcontainer 54 reaches the delivery position to the attaching/detachingdevice 68. On the other hand, the holding member sensor 824 detects thatthe rod holding member 790 reaches the delivery position for receivingthe rod 52S from the rod attaching/detaching device 68 when the rod 52Sremoved from the attaching/detaching device 68 is delivered to the rodcontainer 54. The rod holding member 790 stops at the delivery position,whereupon another rod holding member 790 also stops at a rod removingposition provided under the rod conveyor device 70.

From the sensor bracket 822 on the opposite side of the rod holdingmember 790, a sensor bracket 830 standing up on one of the uppertransverse embers 804 is provided. In the upper portion of the sensorbrackets 828 and 830, a delivery sensor 832 is attached to place a lightemitting portion and a light receiving portion to confront each other,so as to detect that the rod attaching/detaching device 68 receives therod 52S from the rod conveyor device 70. On each bottom portion of apair of the upper transverse members 804, a sensor bracket 834 isoriented downward, and a receiving sensor 836 is provided on the lowerportion of the sensor bracket 834. The receiving sensor 836 consists ofa light emitting portion and a light receiving portion, in which thehorizontal line created in the receiving sensor 836 is positioned tocorrespond to that in the delivery sensor 832. Therefore, the lowerportion of the male screw part 52C of the rod 52S obstructs the lightwhen the rod attaching/detaching device 68 places the rod 52S, removedfrom the suspending rod 52, on the rod holding member 790, whereby thefact that the rod 52S is placed on the rod holding member 790 isdetected.

In the lower portion of the rod conveyor device 70, a rod removing portis provided in order to remove the rod 52S from the conveyor device 70or to furnish the rod 52S to the conveyor device 70. The rod removingport is formed, for example, in the side of the drive sprocket 750 andin the front side of the conveyor device 70 which is in the left side ofFIG. 18. As shown in FIG. 23, protection covers 838 are attached to apair of the vertical members 737, and has a gap 840 so that the rodholding member 790 moves between the protection covers 838. Above theprotection covers 838 on the vertical members 737, sensor brackets 842are provided to protrude forward. A rod detecting sensor 844 consistingof a light emitting portion and a light receiving portion is attached tothe end portions of the sensor brackets 842 for detecting the rod head52B of the rod 52S (see FIG. 23(2)), whereby it is detected that the rod52S is delivered to the rod removing position.

In the embodiment, the boiler module 56 is secured on the bottom of agirder 500 which is composed of I-steel, shown in FIG. 24 to FIG. 26,supported by a number of boiler jacks 60. As shown in FIG. 26, forexample, a pair of the girders 500 is placed parallel and lifted up to apredetermined height by the boiler jacks 60 with the suspending rods 52,and then it is secured to lower faces of jack installing beams 502, astemporary beams on which the boiler jacks 60 are fixedly placed, withgirder upper seats 504 while suspending the boiler module 56. Each jackinstalling beam 502 which is secured with the girder 500 has a workingfloor 506 having a hand-rail 505 at the side portion thereof. Inaddition, a joint floor 508 links the jack installing beam 502 securedthereunder with one of the girder 500 to the jack installing beam 502secured thereunder with the other girder 500, so that the passagebetween the jack installing beams 502 can be freely carried out. Ahand-rail 510 is provided on the side portion of the join floor 508 inorder to prevent the workers from having a fall or the like.

When the boiler module 56 secured under the girder 500 is lifted up anddown, each end of the girder 500 is supported by a balancing device 512which is provided at the lower portion of the suspending rod 52supported by the boiler jack 60. In the embodiment, the balancing device512 is placed to each end portion of each girder 500, and the boilermodule 56 is lifted up and down. Each balancing device 512 has an upperbalance beam 516, as a pair of secondary balance beams, pivotallyprovided to a suspension-exchanging plate 514 and a lower balance beam518 located under the upper balance beam 516.

The upper balance beam 516 and the lower balance beam 518 are arrangedon a perpendicular line to each other. A pair of thesuspension-exchanging plates 514 for supporting both ends of the lowerbalance beam 518 are placed in both sides of the girder 500. The lowerbalance beam 518 is pivotally provided to the lower portion of thesuspension-exchanging plate 514 with a pin 522 and is positioned underthe girder 500. A pair of the upper balance beams 516 are pivotallyprovided in the upper portion of the suspension-exchanging plate 514with a pin 520 and are positioned at both sides of the girder 500. Asshown in FIG. 24, both ends of the longitudinal direction of each upperbalance beam 516 are swingingly supported to the lower portions of thesuspending rods 52 which are located along the longitudinal direction ofthe girder 500 to be supported by a pair of boiler jacks 60 (e.g., theboiler jacks 60A and 60B). The pins 520 and 522, which respectively andpivotally attach the balance beams 516 and 518 to thesuspension-exchanging plate 514, is prevented from sliding out of thebalance beam by a key plate 524, for example, as shown in the pin 522 ofFIG. 25.

As shown in FIG. 24, the lower balance beam 518 has a top plate 526, abottom plate 528 and a pair of side plates 530 linking the top plate 526to the bottom plate 528. The lower portion of the suspension-exchangingplate 514 is inserted between a pair of the side plates 530, and theside plates 530 and the suspension-exchanging plate 514 are coupled bythe pin 522. A number of reinforcing plates 532 provided between the topplate 526 and the bottom plate 528 are placed at strategic points in thelongitudinal direction of the side plates 530. On the central upper faceof the lower balance beam 518, a load receiving system 534 forsupporting a load of the boiler module 56 which acts through the girder500 is provided (see FIG. 25).

The control panel 44 shown in FIG. 1 has a central control system 640shown in FIG. 27. The central control system 640 connects to a number of(e.g., six) local control units 644A, 644B, . . . , through acommunication line 642, and to jack controllers 646A, 646B, . . . ,provided according to the boiler jacks 60A, 60B, 60C, . . . , so that acommunication network is formed by the central control system 640, thelocal control units 644, and the jack controllers 646.

Each jack controller 646 provided according to the boiler jack 60 isstructured, for example, as shown in FIG. 28, and has a centralprocessing unit (CPU) 648, a counter unit 650, an input unit 652, ananalog output unit 654, an output unit 656, and an analog input unit658, and also a communication unit 660 which receives an instructionfrom the central control system 640 or the local control unit 644through the communication line 642 or outputs data or the like to thecontrol system 640 or the control unit 644 through the communicationline 642.

An output pulse is inputted into the counter unit 650 from a strokesensor 662, composed of a linear encoder or a rotary encoder and placedin the boiler jack 60, and computes the pulse which is outputted fromthe stroke sensor 662 by the movement of the ram 76 and outputs theobtained coefficient as a stroke value (stroke displacement) to the CPU648. A signal showing the operating position of the boiler jack 60, asignal showing whether the boiler jack 60 operates normally or not, andso on, are inputted into the input unit 652.

The output side of the analog output unit 654 is connected to a flowcontrolling valve amplifier 664 through a signal line, and converts adigitized speed of the jack which is outputted from the CPU 648 into ananalog signal and outputs the analog signal to the flow controllingvalve amplifier 664 to control the degree of opening a flow regulatingvalve 666, as a flow controlling valve for adjusting the output of theboiler jack 60, through the amplifier 664. The output side of the outputunit 656 is connected to the flow regulating valve 664 and a change-overvalve 670 placed on the hydraulic circuit connecting the boiler jack 60and a hydraulic pump 668, and switches the positions of the change-overvalve 670 when the movement of the ram 76 of the boiler jack 60 ischanged. The analog input unit 658 is connected to a pressure sensor 674for detecting a load that acts on an equalizer jack 672 provided in theboiler jack 60. The analog input unit 658 converts an analog output fromthe pressure sensor 674 into a digital signal, and inputs the digitalsignal as the load that acts on the boiler jack 60 into the CPU 648.

In the embodiment, the local control unit 644A controls, as shown inFIG. 27, the hydraulic pumps 668A to 668D which are respectivelyprovided according to a group of the boiler jacks 60A to 60D supportingone balancing device 512, and allows the hydraulic pumps to carry out asynchronizing control for equating the stroke displacements (the strokevalues) of the boiler jacks 60A to 60D. The other local control units644B . . . carry out the same function. The central control system 640can perform the synchronizing control for more than five boiler jacks60, and is connected through the communication line 642 to a controlunit for the attaching/detaching device, a control unit for the conveyordevice and so on to control the entire system.

That is, the central control system 640 and each of the local controlunits 644 structure a controlling means for carrying out thesynchronizing control for the boiler jacks 60, and have a synchronismcontroller 680 shown in FIG. 29. The synchronism controller 680 has ajack-operation detecting circuit 681, a reference jack selecting circuit682 which is connected to the output side of the jack-operationdetecting circuit 681, and an operating state discerning circuit 686.Into the jack-operation detecting circuit 681, the stroke displacement(the stroke value) of the ram 76 which is obtained on the basis of theoutput signal of the stroke sensor 662 by the jack controller 646provided according to each of the boiler jacks 60, and also the signalof the degree of opening of the valve for determining whether the jackis operated or not, and the like, are inputted. The jack-operationdetecting circuit 681 sends the jack number of the jack of which thedata has been read, and the stroke data, to the reference jack selectingcircuit 682, and inputs the jack number into the operating statediscerning circuit 686.

The reference jack selecting circuit 682 selects the jack having theminimum displacement of stroke as a reference jack on the basis of theinformation from the jack-operation detecting circuit 681 and theoperating state discerning circuit 686, and inputs each strokedisplacement of the jacks into a deviation computing circuit 684oriented toward the output side thereof. The deviation computing circuit684 finds and outputs the deviation between the stroke displacement ofthe reference jack and the stroke displacement of the rest of the jacks.The operating state discerning circuit 686 determines whether or not thejack of the input jack number is in a rated operation or the like;switches a switching circuit 688 connected to the output side of thedeviation computing circuit 684; and inputs the stroke deviation outputfrom the deviation computing circuit 684 into a comparing anddetermining circuit 690 or a deviation-zero determining circuit 692.

The comparing and determining circuit 690 is connected to a referencevalue setting circuit 694, and sends an instruction signal to decreasethe output of the jack of which the deviation exceeds a reference value,to an operation output changing circuit 696 when the deviation outputfrom the deviation computing circuit 684 is higher than a referencevalue (a maximum value) evaluated in the reference value setting circuit694. The operation output changing circuit 696 outputs a signal todecrease the degree of opening of the flow regulating valve 666 assignedto the jack which is controlled to decrease the output, to the jackcontroller 646 assigned with the jack which is controlled, whenreceiving a signal from comparing and determining circuit 690. Theoperation output changing circuit 696 writes the jack number of thejack, of which the operation state is changed, and the operation stateon an operation-state storing circuit 698, and sends a signal to startthe computing of time to a time computation writing circuit 700.

The time computation writing circuit 700 finds the time that elapsedsince the signal was received from the operation output changing circuit696, from the output of a timer 702 connected to the circuit 700, andwrites the obtained time on the operation-state storing circuit 698 incorrespondence to the jack number written on the operation-state storingcircuit 698 by the operation output changing circuit 696. The datawritten on the operation-state storing circuit 698 are used fordiscriminating the operation state in the operating state discerningcircuit 686, and are read by the operation output changing circuit 696.The operation output changing circuit 696 outputs a command signal torecover the output of the controlled jack when the deviation-zerodetermining circuit 692 determines that the deviation found by thedeviation computing circuit 684 is zero. When the deviation is not zero,the operation output changing circuit 696 reads the time written on theoperating-state storing circuit 698, and outputs the command signal tofurther decrease the output when the read time is longer than apredetermined time period.

As shown in FIG. 30, the operation instruction signal output from theoperation output changing circuit 696 is sent out through acommunication unit 706 in the side of the central control system 640 (orthe local control unit 644) to the communication line 642. The operationinstruction signal is read by the CPU 648 of the jack controller 646through the communication unit 660 of the jack controller 646 assignedwith the jack controlled. The CPU 648 outputs a jack speed signalresponding to the operation instruction to the flow controlling valveamplifier 664 through the analog output unit 654 to adjust the degree ofopening of the flow regulating valve 666 in order to control the outputof the boiler jack 60. A jack stroke value output from the counter unit650 is read by the CPU 648. The CPU 648 inputs the jack stroke valuethrough the communication unit 660, the communication line 642 and thecommunication unit 706 into the synchronism controller 680 of thecentral control system 640 and the local control unit 644.

The following is the operation of the lifting jack system, structured asdescribed thus far, according to the embodiment.

Lifting-up of the suspending rod and Detaching of the rod

The ascending mode for lifting up the boiler module 56 will be describedwith reference to schematic views of FIG. 31 to FIG. 33 and flow chartsof FIG. 34 and FIG. 35. As shown in FIG. 31(1), in the initial state,the lower chuck unit 86 of the boiler jack 60 is in a closing state, sothat the suspending rod 52 suspending the boiler module 56 as a liftedbody is supported by the lower chuck unit 86. When the boiler module 56is lifted up, the upper chuck unit 84 is closed, and at the same time,the lower chuck unit 86 is opened, and the neck portion of the rod 52S2,located directly beneath the top rod 52S1 detached, is supported.

That is, the control unit for the attaching/detaching device (not shown)receives a start instruction for the ascending mode, whereupon thecontrol unit operates a pair of the hydraulic cylinders 96 of the upperchuck unit 84 shown in FIG. 3 to retract the cylinder rod. Thereby, theopened chucks 90 and top plates 98 are guided by the slide guides 92 tomove toward each other, so that the top plates 98 are moved in beneaththe head 52B of the rod 52S2, and the closing of the chucks 90 isdetected by ON of the close sensor 104. The control unit closes thechucks 90 of the upper chuck unit 84, and allows the ram 76 to move upto a position in which the top face of the top plate 98 abuts to thehead 52B. After that, the control unit operates the lower chuck unit 86to extend the cylinder rod of the hydraulic cylinder 96. Thereby, thechucks 90 and the top plates 98 of the lower chuck unit 86 are moved tobe away from each other, so that the load of the suspending rod 52shifts to the upper chuck unit 84 by opening the chucks 90 of the lowerchuck unit 86. The opening of the chucks 90 of the lower chuck unit 86is detected by OFF of the open sensor 102.

As shown in FIG. 31(2), after the load of the suspending rod 52 shiftsto the upper chuck unit 84, the ram 76 is continuously driven to move upto reach the up-end, whereby the upper chuck unit 84 pushes up thelarger diametrical head 52B of the chucked rod 52S2 to an operationposition of the detent mechanism 110 (FIG. 31(3)). After the ram 76reaches the up-end, the load of the suspending rod 52 is shifted to thelower chuck unit 86 by closing the lower chuck unit 86 and moving downthe ram 76. The above action is checked by detecting the down-movementof the ram 76 of a little more than 10 mm. The detent mechanism 110 isactuated with the shifting of load, to control the rod 52S2 locatedbeneath the top as shown in FIG. 31(4).

More specifically, when the head 52B of the rod 52S2 reaches theoperation position of the detent mechanism 110, the control unitoperates the hydraulic cylinder 114 shown in FIG. 6 to extend thecylinder rod; turns the end portions of the turnable arms 112 towardeach other; stops (brakes) the rotation of the rod 52S2 to clamp thehead 52B with the pressuring blocks 116 respectively located to the endsof the turnable arms 112. The rear side of the turnable arms 112 moveabove a clamping sensor 132, and the clamping sensor 132 changes intothe ON position, whereby it is detected that the pressuring blocks 116clamps the head 52B of the rod. Therefore, even when a number of rodcoupling portions are between the lower chuck unit 86 as a loadreceiving part and the rod 52S2 under the braking, the rotation of therods is obstructed at the above clamping position.

As shown in FIG. 31(4), the detaching operation for the top rod 52S1directly on the rod 52S2 under the braking is carried out, andsimultaneously, the ram 76 is moved down to return to the starting pointfor the next moving-up drive. The rod can be detached by hand, but, asshown in FIG. 32(1), the rod 52S1 may be rotated in a direction torelease the screwing while being moved up by the aforementioned rodattaching/detaching device 68, and conveyed to the rod container 54 forstoring by the conveyor device 70.

More specifically, the control unit moves up the ram 76 of the boilerjack 60 while driving the transverse drive motor 268; and, as shown inStep 300 of FIG. 34, moves the attaching/detaching chuck 140 of the rodattaching/detaching device 68 to the position above the rod 52S1 to bedetached. The detent mechanism 110 carries out the braking for the rod52S2, whereupon the elevating motor 144 of the attaching/detachingdevice 68 is driven to move down the rotation unit 138. At this time,the control unit drives the rotating motor 142 so that one of thereference hole of home positions 194 is moved directly onto the homeposition detecting sensor 198. The rotation unit 138 is moved down inthe guide frame 242 along the guide rail 248 by the driving of theelevating motor 144. When the attaching/detaching chuck 140 is moveddown with the down-movement of the rotation unit 138 and the head 52B ismoved into the three grip claws 172, the head detecting sensor 227,which is fixedly placed in the sensor mounting ring 214 provided in thelower portion of the steady guide 208 secured in the attaching/detachingchuck 140, is in the OFF position and inputs the head detecting signalinto the control unit. The control unit receives the detecting signal ofthe head detecting sensor 227, whereupon the control unit decreases thedescending speed of the attaching/detaching chuck 140. The tight sensor230 changes into the OFF position, thereby it is determined that theattaching/detaching chuck 140 is moved down to the grip position for therod 52S1. And the rotation unit 138 is stopped moving down (steps 302and 304 in FIG. 34). After that, the control unit operates the pneumaticdriven part 174 of the attaching/detaching chuck 140 to close the threegrip claws 172 for gripping the head 52B (step 306). The grip sensor 220placed in the upper portion of the sensor mounting ring 214 changes intothe ON position, whereby the completion of the gripping process isdetected. At this time, the projection 176 formed on the grip claw 172is engaged with the groove 52E of the head 52B to prevent the rod 52S1from dropping when the rod 52S is separated and suspended by theattaching/detaching chuck 140 (see FIG. 8).

After the completion of the gripping process of the attaching/detachingchuck 140 for the rod 52S1, as indicated with an arrow 340 in FIG.32(1), the attaching/detaching chuck 140 is rotated in a direction torelease the screwing between the top rod 52S1 and the rod 52S2 clampedby the detent mechanism 110, and simultaneously, the elevating motor 144is rotated in reverse to synchronize with the rotation of theattaching/detaching chuck 140. That is, the rotation unit 138 is movedup at a speed corresponding to the speed at which the rod 52S1 isunscrewed (step 310). In step 12, the control unit determines whetherthe rod 52S1 is separated from the rod 52S2 located directly beneath therod 52S1 or not.

More specifically, the control unit reads the output signal from theattaching/detaching sensor 124 (see FIG. 6) located on the side portionof the detent mechanism 110; watches whether the attaching/detachingsensor 124 is in the ON position or not; and determines whether the rod52S1 is separated from the next rod 52S2. When the attaching/detachingsensor 124 is not in the ON position, the control unit returns to step308 due to the determination that the rod 52S1 is not still separated,and repeats the processes in steps 308 and 310. When the sensors 124A to124C are ON and also the sensor 124D is ON, it is determined that therod 52S1 is completely separated from the next rod 52S2, so that theattaching/detaching chuck 140 is moved up to the convey position asshown in FIG. 32(2) (step 314), and then, in step 316, the detached rod52S1 is delivered to the rod conveyor device 70 (see FIGS. 32(3) and(4)).

After the rod 52S1 is separated from the rod 52S2, the hydrauliccylinder 114 of the detent mechanism 110 is actuated, so that thecylinder rod is retracted and the turnable arm 112 is turned in adirection to release the braking, thereby the clamping and braking forthe rod 52S2 is released as shown in FIG. 32(2). The rear portion of theturnable arm 112 is turnably moved above a braking release sensor 130,so that the release of the braking is detected by the braking releasesensor 130. During the release of the braking by the detent mechanism110, the upper chuck unit 84 is closed, and additionally, the load ofthe suspending rod 52 is shifted to the upper chuck unit 84 in the sameway as described above, so that the ram 76 of the boiler jack 60supports the suspending rod 52 through the upper chuck unit 84.

After that, the ram 76 pushes up the suspending rod 52 to move up thehead 52B of the rod 52S2 to the operation position of the detentmechanism 110 (FIG. 32(4)). When the ram 76 reaches the top end, asdescribed above, the control unit closes the lower chuck unit 86, andmoves down the ram 76 slightly to shift the load of the suspending rod52 to the lower chuck unit 86 (FIG. 33(1)). After the load of thesuspending rod 52 is supported by the lower chuck unit 86, the upperchuck unit 84 is opened, and then the detent mechanism 110 is operatedagain to clamp the head 52B of the rod 52S in order to carry out thebraking for the rod 52S3 (FIG. 33(2)).

On the other hand, after the rod attaching/detaching device 68 completesto deliver the rod 52S1 to the rod conveyor device 70, as shown in FIG.33(1), the rod attaching/detaching device 68 is moved to above the nextrod 52S2 for detaching the rod 52S2. The conveyor device 70 delivers therod 51S1, received from the rod attaching/detaching device 68, to aplace where the rod container 54 is located to store the rod 51S1 asshown in FIG. 33(2). In the attaching/detaching device 68, as describedabove, the rotation unit 138 is moved down, and the attaching/detachingchuck 140 grips the head 52B of the rod 52S2 (FIG. 33(3)). After that,the processes beyond FIG. 32(1) are repeated.

The control for the ascending speed of the rotation unit 138 in step 310of FIG. 34 is carried out as shown in FIG. 35.

As shown in step 320, the control unit reads an output signal of therotation detecting sensor 196; obtains the rotational speed of theattaching/detaching chuck 140 (step 320); and computes the ascendingspeed of the attaching/detaching chuck 140 from screw pitch of the screwpart formed on the rod 52S (step 322). The control unit drives theelevating motor 144 on basis of the ascending speed of theattaching/detaching chuck 140, computed above; receives a detectionsignal from the rotary encoder 262; and controls the rotational speed ofthe elevating motor 144 to move up the entire rotation unit 138 at aspeed coordinating with the ascending speed of the attaching/detachingchuck 140 (step 324). At this time, the deviation between the ascendingspeed of the attaching/detaching chuck 140 when the rod 52S1 is rotatedand detached from the rod 52S2, and the ascending speed of the rotationunit 138 by the elevating motor 144 is absorbed by the expansion andcontraction of the compression spring 160 constituting a shaft directiondisplacement absorbing means. The control unit reads an output signal ofthe spring expansion sensor 186 (see FIG. 9), and determines whether thesensor 186 is in the ON position or not (step 326). When the springexpansion sensor 186 is ON, the control unit determines that thedistance between the distance detecting plate 180 and the springexpansion sensor 186 is less than d₀, since the ascending speed of theattaching/detaching chuck 140 is higher than the ascending speed of therotation unit 138, so that the compression spring 160 is extremelycompressed. Accordingly, after the rotational speed of the elevatingmotor 144 is increased for a predetermined amount to increase theascending speed of the rotation unit 138 (step 328), the control unitgoes to step 330. When the spring expansion sensor 186 is not in the ONposition, the control unit goes from step 326 to step 330.

In step 330, the control unit reads an output signal of the springexpansion sensor 188, and checks whether the sensor 188 is in the OFFposition or not. When the spring expansion sensor 188 is OFF, thecontrol unit determines that the distance detecting plate 180 is morethan distance d₁ +5 mm distance from the spring expansion sensor 188since the ascending speed of the attaching/detaching chuck 140 issignificantly slower than the ascending speed of the rotation unit 138,so that the compression spring 160 is stretched out. In consequence, theascending speed of the rotation unit 138 is decreased for apredetermined amount, and then the process for speed control iscompleted. In step 330, when the spring expansion sensor 188 is not inthe OFF position, it is determined that the ascending speed of therotation unit 138 is within the proper range, and the process for speedcontrol is completed and the control unit goes to step 312 in FIG. 34.

Coupling the rods and Lifting down the suspending rod

When the suspending rod 52 is lifted down while the rod 52S is coupledto the top of the suspending rod 52, the operation is carried out asfollows.

In the initial stage when the rods 52S are coupled, as shown in FIG.36(1), the attaching/detaching chuck 140 of the rod attaching/detachingdevice 68 is positioned at a rod delivery position of the rod conveyordevice 70. The upper chuck unit 84 is opened, and the lower chuck unit86 is closed and supports the load of the suspending rod 52. The rod52S2 located at the top of the suspending rod 52 is clamped at the head52B thereof by the pressuring block 116 of the detent mechanism 110 soas to be under the braking.

In the above state, the rod 52S1 which is to be coupled onto the rod52S2 is transferred onto the rod conveyor device 70 from the rodcontainer 54 to be conveyed under the attaching/detaching chuck 140(FIGS. 36(2) and (3)). The control unit moves up the ram 76 of theboiler jack 60; moves the upper chuck unit 84 to the neck portion of therod 52S2; and closes the upper chuck unit 84 in order to be inpreparation for receiving the load of the suspending rod 52. After thecontrol unit allows the attaching/detaching chuck 140 of theattaching/detaching device 68 to grip the head 52B of the rod 52S1 (FIG.36(4)), the control unit drives the transverse drive motor 268 totransfer the rod 52S1 to above the suspending rod 52 as shown in FIG.37(1) (step 350 in FIG. 39).

After that the control unit drives the elevating motor 144 to move downthe attaching/detaching chuck 140 through the rotation unit 138 at a lowpace (step 352). As shown in FIG. 37(2), the attaching/detaching chuck140 is moved down to until the (lower) end of the male screw part 52C ofthe rod 52S1, gripped by the chuck 140, confronts the female screw part52D of the rod 52S2, and the rod 52S1 is set on the rod 52S2. That is,the control unit watches an output signal from the attaching/detachingsensor 124C. The output of the sensor 124C changes to OFF, whereby thecontrol unit detects that the male screw part 52C of the rod 52S1 isfaced to the female screw part 52D of the rod 52S2 and the rod 52S1 ismoved down to the coupling position and set on the rod 52S2, and stopsthe downward movement of the rotation unit 138 (step 354).

Next, while the downward movement of the rotation unit 138 is stopped,as indicated with an arrow 342 of FIG. 37(3), the control unit rotatesthe rotating motor 142 in a direction to screw the rods 52S1 and 52S2 toeach other at a low speed (e.g., 50 rpm when screw pitch is 12 mm) torotate the attaching/detaching chuck 140 one turn (step 356). Thecontrol unit finds load torque of the rotating motor 142 from a drivecurrent of the rotating motor 142; watches an output signal of thespring expansion sensor 188; and determines whether the screw parts ofboth of the rods 52S1 and 52S2 are engaged with each other or not (step358).

More specifically, the rod 52S1 screws downward as the screw part of therod 52S2 is being engaged. Therefore, the attaching/detaching chuck 140has a displacement in the shaft direction with the movement of the rod52S1, and is being moved down while stretching out the compressionspring 160 through the slide shaft 156. In consequence, the distancedetecting plate 180 secured to the slide shaft 156 is moved togetherwith the slide shaft 156, and the output of the spring expansion sensor188 changes to OFF when the distance between the spring expansion sensor188 and the distance detecting plate 180 exceeds the d₁ +5 mm. Theexpansion sensor 188 changes into the OFF position, whereby the controlunit determines that the screw parts of both of the rods 52S1 and 52S2are engaged (screwed) with each other. Since the rods 52S1 and 52S2 aremoved down in the state that the rod 52S1 is pulled upward by thecompression spring 160, both of the screw parts of the rods are screwedwith each other by using back-lash of the screw faces.

When the control unit determines that the screw parts of both of therods are not engaged, the control unit goes to step 360 to detectwhether the obtained load torque of the rotating motor 142 is less thana predetermined value or not. When the torque is less than thepredetermined value, returning to step 356, the attaching/detachingchuck 140 is continued to be rotated at a low speed. In step 360, whenthe load torque of the rotating motor 142 is more than the predeterminedvalue, the control unit determines that the screw parts of both the rods52S1 and 52S2 are not engaged and drag is occurring, and stops the driveof the rotating motor 142, and alerts an operator to the irregularity byan alarm (step 362).

It should be mentioned that even when the rod 52S1 is set on the rod52S2 with its axis being slightly deviated, the attaching/detachingchuck 140 is supported in an oscillating state by the spring coupling170, so that the deviation of the rotation shaft is absorbed by thespring coupling 170, thereby the screw parts of the rods 52S1 and 52S2can be smoothly engaged. Where both axes of the rods 52S1 and 52S2 aredeviating from each other when the rod 52S1 is set on the rod 52S2, bothaxes can be easily aligned by slowly rotating the rod 52S1 (theattaching/detaching chuck 140). More specifically, an end of a screw hasa taper shape for smooth engagement. Therefore, the attaching/detachingchuck 140 gripping the rod 52S1 is supported in an oscillating state bythe spring coupling 170, so that when the attaching/detaching chuck 140is rotated at a slow speed, a lower taper face of the male screw part ofthe rod 52S1 is slipped into a upper taper face of the female screw partof the rod 52S2, thereby both of the axes are naturally aligned.

Confirming that the screw parts of the rods 52S1 and 52S2 are engagedwith each other in step 358, the control unit rotates theattaching/detaching chuck 140 at a predetermined speed in a direction ofscrewing (step 364). The elevating motor 144 is driven in correspondenceto the descending speed of the attaching/detaching chuck 140 by screwingthe rod 52S1 downward, and the descending speed of the rotation unit 138is controlled (step 366). Whether or not the rods 52S1 and 52S2 arecompletely coupled to each other is determined (step 368).

Where screw pitch is, for example, 12 mm, the rotational speed of theattaching/detaching chuck 140 has a speed at which the descending speedof the attaching/detaching chuck 140 is approximately 600 mm/min.Whether the rods are completely coupled or not is determined, when theattaching/detaching sensors 124A and 124C (see FIG. 6) are in the OFFposition and the load torque of the rotating motor 142 exceeding a setvalue is detected. In the embodiment, the coupling state is detected bytwo sensors 124A and 124C, so that even when any one of the sensors 124Aand 124C is in the OFF position by reason of vibration, oscillation orthe like, the completion of the coupling is not determined, resulting inthe improved reliability of the apparatus.

In step 368, when the coupling of the rods 52S1 and 52S2 is notcompleted, the control unit returns to step 364 to control the rotationand the downward movement of the attaching/detaching chuck 140. When thecoupling is completed, the control unit goes to step 370 to stop therotation of the attaching/detaching chuck 140 and the downward movementof the rotating unit 138. After that, as shown in FIG. 37(4), thecontrol unit opens the attaching/detaching chuck 140, and moves up thechuck 140 to the convey position for the rod 52S (step 372), and thenthe coupling control for the rod 52S is completed.

The control for the descending speed of the rotation unit 138 in thecoupling of the rods is carried out as shown in FIG. 40. The controlunit computes the rotational speed of the attaching/detaching chuck 140from an output signal form the rotation detecting sensor 196, andcomputes the descending speed of the attaching/detaching chuck 140(steps 380 and 382). The control unit drives the elevating motor 144 tomove down the rotation unit 138 at a speed commensurate with thedescending speed of the attaching/detaching chuck 140. At this time, thecontrol unit watches the output signals from the spring expansionsensors 188 and 186 (see FIG. 9), and controls the descending speed ofthe rotation unit 138 and the descending speed of theattaching/detaching speed not to differ from each other.

More specifically, as shown in step 386, the control unit checks whetherthe spring expansion sensor 188 is in the OFF position or not. When thespring expansion sensor 188 is OFF, it is determined that the descendingspeed of the rotation unit 138 is slower than the descending speed ofthe attaching/detaching chuck 140, and the compression spring 160 isstretched out. The control unit increases the rotational speed of theelevating motor 144 for a predetermined amount to increase thedescending speed of the rotation unit 138 as shown in step 388, and goesto step 390. When it is determined that the spring expansion sensor 188is not OFF in step 386, the control unit goes to step 390 to checkwhether the spring expansion sensor 186 is ON or not. When the springexpansion sensor 186 is ON, it is determined that the descending speedof the rotation unit 138 is higher than the descending speed of theattaching/detaching chuck 140, so that the descending speed of therotation unit 138 is decreased for a predetermined amount (step 392),and the processes for controlling the descending speed is completed.When the spring expansion sensor 186 is not ON in step 390, the controlunit determines that the descending speed of the rotation unit 138 isnormal, and completes the processes.

The control unit opens and moves up the attaching/detaching chuck 140 tothe predetermined position after the coupling of the rod 52S1, and opensthe lower chuck unit 86 and shifts the load of the suspending rod 52 tothe upper lower chuck unit 84. After that, the control unit activatesthe hydraulic cylinder 114 of the detent mechanism 110 for releasing thebraking applied to the rod 52S2, and moves down the ram 76 of the boilerjack 60 to lift down the suspending rod 52. When the suspending rod 52is lifted down to a position which the head 52B of the rod 52S1 reachesin the vicinity of the braking position of the detent mechanism 110, thelower chuck unit 86 is closed and the load of the suspending rod 52 isshifted to the lower chuck unit 86. After the shifting of the load ofthe suspending rod 52, the ram 76 is moved up again (FIGS. 38(1) to(3)).

The rod attaching/detaching device 68 is moved to above of the rodconveyor device 70 in order to receive the next rod 52S to be coupled(FIG. 38(1)). The rod conveyor device 70 receives the next rod 52S to becoupled from the rod container 54, and conveys the received rod 52S tothe lower portion of the rod attaching/detaching device 68. The conveyedrod 52S is gripped by the attached/detached device 68 and transferredabove the suspending rod 52 to be coupled with the conveyed rod 52S(FIG. 38(4)). Simultaneously, the upper chuck unit 84 is moved up to thesupport position for the rod 52S1 by the ram 76 and closed. After that,the processes beyond FIG. 37(2) are repeated.

The control unit watches the outputs from the spring expansion sensors184 and 190 to carry out a lower-limit position control and anupper-limit position control of the attaching/detaching chuck 140. FIG.41 is a flow chart of the upper-limit position control of the chuck inthe coupling of the rod 52S. FIG. 42 is a flow chart of the lower-limitposition control of the chuck in the coupling of the rod 52S.

While the control unit controls the rotation of the attaching/detachingchuck 140 and the downward movement of the rotation unit 138, as shownin step 400 of FIG. 41, the control unit reads the output signal fromthe spring expansion sensor 184, detecting the limit of the compressionof the compression spring 160, at predetermined intervals; anddetermines whether or not the sensor 184 is ON. When the springexpansion sensor 184 is not ON, but is OFF, the control unit goes tostep 402 to determines whether or not the spring expansion sensor 186 isON. When the spring expansion sensor 186 is not ON, the control unitcompletes the process in this step. When the spring expansion sensor 186is ON, it is determined that the descending speed of theattaching/detaching speed is lower than the descending speed of therotation unit 138, so that the descending speed of the rotation unit 138is decreased for a predetermined amount, and then the process in thisstep is completed.

In step 400, when ON of the spring expansion sensor 184 is detected, thedescending speed of the attaching/detaching chuck 140 is lower ascompared with the descending speed of the rotation unit 138, so thatmechanical breakage may occur. In consequence, the control unit goes tostep 406 to stop the downward movement of the rotation unit 138 whilerotating the attaching/detaching chuck 140. After that, the control unitdetermines whether the rotation of the attaching/detaching chuck 140 isregular or not (step 408). When the rotation of the attaching/detachingchuck 140 is irregular, the control unit goes to step 416 to stop therotation of the chuck 140, and rises an alarm, and then completes thisprocess.

The determination whether the rotation of the attaching/detaching chuck140 is regular or not is carried out as shown in FIG. 43.

A motor driving discriminate device (not shown) outputs a rotationoutput signal "H" as shown in FIG. 43(1) when electric current orvoltage is applied to the rotating motor 142 and the rotating motor 142is rotationally driven. The rotation detecting sensor 196 changes intothe OFF position when the rotation detecting slot 192 of the rotationdetecting plate 178 is positioned above the sensor 196. When any partother than the rotation detecting slot 192 is positioned above thesensor 196, the rotation detecting sensor 196 detects reflected lightfrom the rotation detecting plate 178 and changes into the ON position.Therefore, when the rotation output of the motor is produced by rotatingthe rotating motor 142, and the attaching/detaching chuck 140 isregularly rotated, as shown in FIG. 43(2), the sensor signal havingprecisely spaced pulses is outputted. When the attaching/detaching chuck140 is regularly rotated, an attaching/detaching chuck rotationdiscriminate device (not shown) outputs "H" showing the regular rotationas shown in FIG. 43(3) by using the rotation output signal of therotating motor 142 and the precisely spaced pulses output from therotation detecting sensor 194. When the rotation detecting sensor 196does not output pulse although the rotation output signal is "H", "L"showing that the attaching/detaching chuck 140 is not regularly rotatedis outputted. The control unit reads the output signal from theattaching/detaching chuck rotation discriminate device in step 408 ofFIG. 41, and determines by the above output signal whether theattaching/detaching chuck 140 is regularly rotated or not.

When the attaching/detaching chuck 140 is regularly rotated, the controlunit goes to step 410 to check that the spring expansion sensor 186 isOFF. When the sensor 186 is OFF, the control unit determines that theattaching/detaching chuck 140 is moved down to the regular position;restarts the control for the downward movement of the rotation unit 138;and completes this controlling process (step 412).

When the spring expansion sensor is ON, the control unit goes from step410 to step 414 to determine whether or not a predetermined time haselapsed since the downward movement of the rotation unit 138 wasstopped. When the predetermined time has not elapsed since the downwardmovement of the rotation unit 138 was stopped, the control unit returnsto step 406 to retain the downward movement of the rotation unit 138 inthe stopping state. In step 414, when the predetermined time has elapsedsince the downward movement of the rotation unit 138 is stopped, thecontrol unit determines that the rotation of the attaching/detachingchuck 140 is not transmitted to the rod 52S for reasons of the loosenessof chuck or the like, so that the control unit stops the rotation of theattaching/detaching chuck 140, and alerts an operator to theirregularity by an alarm (step 416), and then completes this process.

Next, the lower-limit position control of the chuck in the coupling ofrod 52S is carried out as follows.

While the control unit controls the rotation of the attaching/detachingchuck 138 and the downward movement of the rotation unit 138, as shownin step 420 of FIG. 42, the control unit reads the output signal fromthe spring expansion sensor 190, detecting the stretching limit of thecompression spring 160, at predetermined intervals; and determineswhether the sensor 190 is OFF or not. When the spring expansion sensor190 is not OFF, the control unit continues to control the rotation ofthe attaching/detaching chuck 140 and the downward movement of therotation unit 138 (step 422), and then completes this process. When thespring expansion sensor 190 is OFF, the descending speed of theattaching/detaching chuck 140 is higher than that of the entire rotationunit 138, so that mechanical breakage may occur, therefore, the controlunit increases the descending speed of the rotation unit 138 for apredetermined amount (step 424). After that, the control unit determineswhether or not the descending speed of the rotation unit 138 is withinthe limit (step 426). When the descending speed of the rotation unit 138does not reach the upper limit, the control unit complete this process.However, when the descending speed of the rotation unit 138 reaches theupper limit, as shown in step 428, the control unit decreases therotational speed of the attaching/detaching chuck 140 for apredetermined amount to decrease a speed of screwing of the rods 52S,and then completes this process. Note that the upper-limit positioncontrol and the lower-limit position control of the chuck are alsocarried out when the boiler module 56 is lifted up.

Deliver and convey of a rod

The delivery of the rod 52S between the rod attaching/detaching device68 and the rod conveyor device 70, and the conveyance of the rod 52S bythe rod conveyor device 70 are carried out as follows (see FIG. 18 toFIG. 23).

In a rod storing mode of when the rod 52S is detached, the conveyingchain 752 of the rod conveyor device 70 is driven and rotated in acounterclockwise direction of FIG. 18. The holding member sensor 824,which is placed at the end portion of the transverse frame as a deliveryposition for the rod, changes into the ON position after detectingreflected light from the striker 822 placed to the side portion of therod holding member 790 moving toward the sensor 824, and sends out theON signal to the control unit for the conveyor device which is designedon the control panel 754. The control unit detects that the rod holdingmember 790 reaches the delivery position by using the ON signal from thesensor 824, and stops the drive motor 740 to stop the holding member 790at the delivery position.

On the other hand, when the rod attaching/detaching device 68 detachesthe rod 52S from the suspending rod 52 by using the attaching/detachingchuck 140, the control unit for the attaching/detaching device drivesthe transverse drive motor 268 to move the rod attaching/detachingdevice 68 to above the deliver position of the rod conveyor device 70.The control unit for the attaching/detaching device receives theinformation that the rod holding member 790 is at the delivery positionfrom the central control system 640, and drives the elevating motor 144of the rod attaching/detaching device 68 to move down the rod 52S,gripped by the attaching/detaching chuck 140, through the rotation unit138. The rod 52S is moved down and the end portion of the rod 52Schanges the receiving sensor 836 into the OFF position. The OFF signalof the sensor 836 is sent to the control unit for the conveyor deviceand the control unit for the attaching/detaching device through thecentral control system 640, whereupon the control unit for theattaching/detaching device opens the attaching/detaching chuck 140 ofthe rod attaching/detaching device 68; moves up the rotation unit 138;and moves the attaching/detaching device 68 to the detaching positionfor detaching the next rod 52S.

When the rotation unit 138 is moved up, the control unit for theconveyor device drives the drive motor 740 to circulate the conveyingchain 752 in a counterclockwise direction of FIG. 18. The rod holdingmember 790 holding the rod 52S is moved down along the guide rail 786and reaches the removing position placed in the lower portion of the rodconveyor device 70, whereupon the rod detecting sensor 844 changes intothe OFF position and outputs the detection signal. Thereby the controlunit for the conveyor device stops the drive motor 740 to stop the rod52S at the removing position. When it is determined that the roddetecting sensor 844 is in the ON position and the rod 52S is removedfrom the rod holding member 790 by a worker, the control unit drives thedrive motor again and stops the rod holding member 790 at the deliveryposition.

On the other hand, in a removing mode in which the rod 52S is coupled tothe end of the suspending rod 52, when a worker places the rod 52S ontothe rod holding member 790 stopping at the removing position, the roddetecting sensor 844 detects the placing of the rod 52S. Thereby, thecontrol unit for the conveyor device drives the drive motor to circulatethe conveying chain 752 in a clockwise direction of FIG. 18, andtransfers the rod 52S toward the delivery position of the end of thetransverse frame 738. The holding member sensor 826 settled at thedelivery position detects the striker 822 combinedly moved with the rodholding member 790 and outputs the ON signal. Thereby, the circulationof the conveying chain 752 is stopped, and chuck 140 of the rodattaching/detaching device 68 in the standby state above the deliveryposition is moved down and grips the head 52B of the rod 52S conveyed tothe delivery position. When the attaching/detaching chuck 140 grippingthe rod 52S is moved up and the lower end of the rod 52S is moved abovethe delivery sensor 832, the sensor 832 changes into the ON position.Thereby, the control unit for the conveyor device circulates theconveying chain 752 in the clockwise direction of FIG. 18 again in orderto convey the new rod 52S to the delivery position. When the liftingunit 138 of the rod attaching/detaching device 68 is moved up to apredetermined height, the control unit for the attaching/detachingdevice drives the transverse drive motor 268 to move the rodattaching/detaching device 68 to above the suspending rod 52.

Synchronizing control of the jack

The synchronizing control for lifting up and down the boiler module 56in parallel is carried out as follows.

FIG. 44 is a program analysis diagram (PDA) for explaining thesynchronizing control of the jacks when the boiler module 56 is liftedup. The synchronizing control of the jacks will be described below withreference to FIG. 27 to FIG. 30.

At the start of operating the boiler jacks 60, the central controlsystem 640 or the local control units 644A, 644B, . . . , gives anoperation instruction for operating each of the boiler jacks 60 with theequal output, for example, the rated output, to the jack controller 646assigned with one of the jacks 60. The central control system 640 or thelocal control unit 644A, 644B, . . . , successively reads the strokevalue (the stroke displacement) of the boiler jack 60 to which the jackcontroller 646 outputs, a signal showing the operating state of thedegree of opening of the valve, and so on at predetermined intervals;and gives the information to the jack-operation detecting circuit 681 inthe synchronism controller 680 (box 710 in FIG. 44). The jack-operationdetecting circuit 681 determines whether or not the jack which iscontrolled (the controlled jack) is in operation (box 711). When thecontrolled jack is in operation, the circuit 681 inputs a jack number ofthe controlled jack into the operating state discerning circuit 686, andsends the jack number and the stroke displacement from the start of theoperation to the reference jack selecting circuit 682.

The operating state discerning circuit 686 determines whether thecollected jack is in rated operation or not, by using the operationstate of the controlled jack which is written on the operation-statestoring circuit 698 (box 712), and inputs the result of thedetermination into the reference jack selecting circuit 682. Thereference jack selecting circuit 682 writes the jack number and strokedata, inputted from the jack-operation detecting circuit 681, in theinternal memory; compares the stroke values of the jacks in ratedoperation with each other; selects a jack having the minimumdisplacement from the initial position; and defines the selected jack asthe reference jack (boxes 713 and 714).

As shown in boxes 715 to 717, when the controlled jack judged as beingin operation from the jack data is not the reference jack, the referencejack selecting circuit 682 sends the stroke data of the reference jackand the controlled jack to the deviation computing circuit 684 insequence in order to find deviation δ between the reference jack and thecontrolled jack. The operating state discerning circuit 686 determineswhether the controlled jack is in a decelerating operation or not (box718). When the controlled jack is not in the decelerating operation, butin the rated operation, the circuit 686 connects the deviation computingcircuit 684 with the comparing and determining circuit 690 through theswitching circuit 688 to input the stroke deviation δ found by thedeviation computing circuit 684 into the comparing and determiningcircuit 690 with respect to the controlled jack (box 719).

The comparing and determining circuit 690 compares the input deviation δwith a reference value (e.g., 2 mm) as the maximum value set in thereference value setting circuit 694; and outputs a signal to decreasethe output to the operation output changing circuit 696 when thedeviation δ exceeds the maximum value; but does not output the signalwhen the deviation δ does not reach the maximum value. The operationoutput changing circuit 696 continues the rated operation of thecontrolled jack when the signal is not inputted from the comparing anddetermining circuit 690, and outputs a first-step decelerating commandsignal to change the output of the controlled jack into a predeterminedoutput (60% of the rated output in the embodiment) when the signal isinputted from the circuit 690 (box 720). The operation command signal issent from the central control system 640 or the local control unit 644through the communication line 642 to the jack controller 646 assignedwith the controlled jack. The jack controller 646 receiving the signaldecreases the output of the controlled boiler jack 60 to 60% of therated output through the flow regulating valve 666. As a result, forexample, when the boiler jack 60 is operated in the ascending mode, theascending speed of the ram 76 is decreased to 60% from the rating (100%)at point a shown in FIG. 46.

Upon outputting the first-step decelerating command for the controlledjack, the operation output changing circuit 696 writes that thecontrolled jack is in the first-step decelerating state on theoperation-state storing circuit 698, and sends a time computing startsignal to the time computing writing circuit 700. The time computingwriting circuit 700 computes the time from time t₁ receiving theinstruction from the operation output changing circuit 696 on basis ofthe output of the timer 702, and writes the computed time on theoperation-state storing circuit 698 in accordance to the controlled jack(box 721).

In box 718, from the operation state stored in the operation-statestoring circuit 698, the operating state discerning circuit 686determines that the controlled jack is in the decelerating operation,and connects the deviation computing circuit 684 with the deviation-zerodetermining circuit 692 by switching the switching circuit 688. Thereby,the deviation δ found by the deviation computing circuit 684 is inputtedto the deviation-zero determining circuit 692. The deviation-zerodetermining circuit 692 determines whether or not the deviation δbetween strokes of the controlled jack and the reference jack is morethan zero (box 722). When the deviation is δ>0, the deviation-zerodetermining circuit 692 outputs the deviation δ>0 to the operationoutput changing circuit 696. Upon inputting a signal showing δ>0 fromthe deviation-zero determining circuit 692, the operation outputchanging circuit 696 reads the operation state of the controlled jack,written on the operation-state storing circuit 698, and the time sincethe first-step decelerating command is outputted; determines theoperation state of the jack as shown in FIG. 45; and determines whetherthe predetermined time has elapsed since the first-step deceleratingcommand was outputted. When the predetermined time has elapsed, theoperation output changing circuit 696 outputs a second-step deceleratingcommand signal or a third-step decelerating command signal.

More specifically, when the controlled jack is in the first-stepdecelerating operation, the operation output changing circuit 696determines whether or not the predetermined time, for example, eightseconds has elapsed since the first-step decelerating operation wasstarted. When eight seconds has not elapsed since the first-stepdecelerating operation was started, the first-step deceleratingoperation is continued. When eight seconds elapsed and the time changesto time t₂, the operation output changing circuit 696 outputs thesecond-step decelerating command signal to further decrease the outputof the controlled jack (e.g., the decrease of 40% of the rating), andwrites that the controlled jack is in the second-step deceleratingoperation on the operation-state storing circuit 698. With δ>0 and thecontrolled jack being in the second-step decelerating operation, whenthe predetermined time (e.g., three seconds) has elapsed since thesecond-step decelerating operation was started and the time changes totime t₃, the third-step decelerating operation command signal isoutputted to operate the controlled jack at, for example, 20% of therating.

When the deviation δ found by the deviation computing circuit 684 ischanged to less than zero, that is, when δ≦0 is confirmed, thedeviation-zero determining circuit 692 inputs the above information intothe operation output changing circuit 696. Upon receiving the signalshowing δ≦0 after the decelerating operation for the controlled jack isstarted, the deviation-zero changing circuit 696 converts thedecelerating operation of the control jack back into the rated operation(box 726); clears the computing of time in the time computing writingcircuit 700; and revises the operation states of the controlled jack,written on the operation-state storing circuit 698, to the ratedoperation (box 727). After that, the above processes are repeated. FIG.46 shows the stroke changing of the control in which the third-stepdecelerating operation is carried out, and the operation output changingcircuit 696 receives the signal, showing δ≦0, from the deviation-zerodetermining circuit 692 at time t₄, and the output of the controlledjack is converted back into the rated operation of the early stage.Where a number of jacks have the stroke deviation exceeding thereference value, each jack is controlled in the same way. Thesynchronizing control for the boiler jacks 60 in the descending mode forlifting down the boiler module 56 is also carried out in the same way.

As described thus far, the output of each jack is decreased on basis ofthe jack having the minimum stroke displacement, and the strokedisplacement of the controlled jack is controlled to be equal to thestroke displacement of the reference jack, so that the boiler module 56as a massive body can be lifted up and down in approximately horizontalwith the simple control. When the output of the controlled jack iscontrolled, since the output is controlled to be decreased at apredetermined output rate with respect to the rating, the control doesnot result in a complicated control and any costly sensor or the like isnot needed, thereby simplifying the apparatus and reducing the cost. Theoutput is decreased step by step in several times, so that the strokedisplacement of the controlled jack is prevented from overshooting underthe stroke displacement of the reference jack.

It is should be mentioned that when the deviation is not δ≦0 after thepredetermined time, for example, two seconds has elapsed from the inputof the third-step decelerating command, a signal to stop the operationuntil the stroke displacement of the controlled jack agrees to thedisplacement of the reference jack may be outputted, or alternatively, astopping operation command instead of the three decelerating operationcommand may be outputted.

In the above embodiment, the synchronizing control, carried out inoperations for lifting up and down the massive body through thesuspending rod 52, is described, but the synchronizing control can becarried out in operations for lifting up and down the massive body bysynchronizing a number of jacks which are placed under the massive body,such as building construction.

In the synchronizing control for the jacks, when a difference in thestroke displacement between the jacks occurs, the difference is absorbedby the balancing device 512 supporting the girder 500. For example, inthe ascending mode, when the difference occurs in the ascending speedsof the rams 76 of the boiler jacks 60A, 60B, shown in FIG. 24, each ofwhich supports the upper balance beam 516 through the suspending rod 52,and the speed of the boiler jack 60B for lifting up the rod exceeds thespeed of the boiler jack A, the upper balance beam 516 rotates about thepin 520 in a clockwise direction of FIG. 24. Additionally, the upperbalance beam 516 is pivotally provided to a suspension-exchanging plate514, and a cylindrical seat 550 and a balance receiving seat 608 areplaced between a nut 551 of the suspending rod 52 as a coupler and theupper balance beam 516, and also the upper balance beam 516 is supportedthrough the cylindrical seat 550 and the balance receiving seat 608. Inconsequence, even when the upper balance beam 516 tilts, the tilt isabsorbed by the cylindrical seat 550 and the balance receiving seat 608,so that the suspending rod 52 is prevented from receiving a largebending stress. The runout of the shaft of the suspending rod 52 isavoided, and also it is avoided that the detaching process for the rod52S is complicated or the use of the rod 52S is impossible by reason ofthe bending of the suspending rod 52. The above description is the samewith the descending mode.

Where the difference in the ascending speed occurs between the right andleft sides or both ends in the longitudinal direction of the girder 500,that is, where the difference in the ascending speed occurs between thesuspending rods 52 under the boiler jack 60A and the boiler jack 60Cshown in FIG. 25 or in both sides of FIG. 26 in a directionperpendicular to paper of FIG. 26, the difference of the speed isabsorbed by the load receiving system 534 placed between the lowerbalance beam 518 and the girder 500. For example, when the ascendingspeed of the rod 52 connected to the boiler jack 60A exceeds theascending speed of the rod 52 connected to the boiler jack 60C, thelower balance beam 518 rotates about the center of the upper face of aspherical seat 536, supporting the girder 500 through a receiving seat540, in a clockwise direction of FIG. 25. The lower balance beam 518 ispivotally provided on the suspension-exchanging plate 514, connected tothe lower end of the suspending rod 52, through the pin 522, so that itis avoided that the bending stress acting to the suspending rod 52allows the suspending rod 52 to have the runout of the shaft, therebypreventing the suspending rod 52 from damaging being damaged. The abovedescription is the same with the difference in the ascending speedproduced at both end of the girder 500 in the longitudinal direction,and also with the descending mode.

Note that, when the deviation exceeding the predetermined value occursbetween the stroke displacement of the boiler jacks, the control unitcarries out the aforementioned synchronizing control to decrease theoutput of the boiler jack having the larger stroke displacement, andcontrol the ascending speed to even the strokes of the boiler jacks.

Industrial Availability

As described thus far, a lifting jack, a method of coupling suspendingrods, and a lift control method according to the present invention areappropriate to be used in a connecting and separating operation of asuspending rod and the handling of the suspending rod, and a liftingoperation using a group of jacks, when a boiler module of a large scaleelectric-power plant or the like is lifted with the suspending rod.

We claim:
 1. A rod attaching/detaching device for a lifting jack thatattaches and detaches rods to and from an end of a suspending rod, whenthe suspending rod for lifting is formed by screwing and coupling therods in an axis direction and a top end portion of the suspending rod islifted up and down by the lifting jack, comprising:chuck means forchucking a head part of the rod; a rotation unit having a shaft drivingto be rotated by a rotating motor and connected with said chuck means,and having a displacement absorbing means on a path of linking an outputshaft of the rotating motor to said chuck means; elevating means forvertically moving said rotation unit in response to a screw pitch of therods; a rotation sensor detecting the rotation of said chuck means; andcontrolling means for controlling vertical movement of said rotationunit by said elevating means based on and output signal of said rotationsensor, so that the vertical movement coincides with detected rotationof the said chuck means.
 2. The rod attaching/detaching device accordingto claim 1, wherein said displacement absorbing means, placed on thepath of linking the output shaft of the rotating motor to said chuckmeans, has a shaft direction displacement absorbing means and a rotationshaft run-out displacement absorbing means.
 3. A method of couplingsuspending rods, which is for coupling a rod to an end of a suspendingrod used for lifting, the suspending rod being formed by screwing andcoupling the rods in an axis direction, comprising the steps of:opposinga screw part of the rod to a screw part of a top rod of the suspendingrod while gripping the rod with a rotation chuck means; detecting apredetermined shaft direction displacement of the chuck means, caused byrotating the chuck means at a low speed at the opposing position; androtating the chuck means at a high speed using a rotation unit whilemoving down the rotation unit in response to a screw pitch of the rod tocouple the rods by screwing.
 4. The method of coupling suspending rodsaccording to claim 3, wherein the predetermined amount of the shaftdirection displacement of the chuck means is a value corresponding to apitch of a rod coupling screw.
 5. A method of coupling suspending rodsfor coupling a rod to an end of a suspending rod used for lifting, whichis formed by screwing and coupling the rods in an axis direction,comprising the steps of:gripping the rod in a suspending state with arotation chuck means; rotating the rotation chuck means at a low speedwhile the rod is being centered on a screw part of a top rod of thesuspending rod; inserting a screw part of the gripped rod by moving downthe rotation chuck means; detecting a predetermined shaft directiondisplacement of the rotation chuck means as the rod is rotated at a lowspeed indicating engagement of the rod with the suspending rod by usingback-lash of a screw face; and rotating the rotation chuck means at ahigh speed while moving down a rotation unit, driven to rotate the chuckmeans, in response to a screw pitch of the rod to couple the rods byscrewing.
 6. A lifting jack for lifting an upper portion of a suspendingrod that is formed by screwing and coupling rods in an axis direction,comprising:a jack placed on a supporting frame that lifts the suspendingrod; a rod attaching/detaching means positioned above the jack forgripping the rod and attaching and detaching the rod to and from thesuspending rod, the rod attaching/detaching means being rotatable andvertically movable toward and away from an attaching/detaching position;and a rod convey means for conveying the rods to the rodattaching/detaching means, the rod convey means being provided on amoving route of said rod attaching/detaching means, and traversingbetween a rod storing position and a deliver position that delivers therods to the rod attaching/detaching means.
 7. The lifting jack accordingto claim 6, wherein said rod convey means has a frame assembled withmodules and having a direction changing portion of a sprocket to changedirections of a conveyed body, and is changed in a traversing distancethereof according to changing of working positions of the deliverposition for the rod to said attaching/detaching means and the rodstoring position.